See also:

• MAMMALIA (from Lat. mamma, a teat or breast)

MAMMALIA (from See also:

• LAT

Lat. mamma, a teat or See also:

• BREAST (a word common to Teutonic languages, cf. the Ger. Brust, possibly connected with an O. Sax. brustian, to bud)

breast)  , the name proposed by the See also:

• SWEDISH

Swedish naturalist See also:

• LINNAEUS

Linnaeus for one of the classes, or See also:

• PRIMARY

primary divisions, of vertebrated animals, the members of which are collectively characterized by the presence in the See also:

• FEMALES

females of See also:

• SPECIAL

special glands secreting See also:

• MILK (0. Eng. meoluc; from a common Indo-European root, cf. Lat. mulgere, Gr. ?t dXyetv)

milk for the nourishment of the See also:

• YOUNG
• YOUNG, A
• YOUNG, ARTHUR (1741-1820)
• YOUNG, BRIGHAM (1801-1877)
• YOUNG, CHARLES MAYNE (1777–1856)
• YOUNG, EDWARD (1683–1765)
• YOUNG, JAMES (1811-1883)
• YOUNG, THOMAS (1773-1829)

young . With the exception of the lowest See also:

• GROUP

group, such glands always communicate with the exterior by means of the teats, nipples or mammae, from which the class derives its name . The class-name (modified by the See also:

• FRENCH
• FRENCH, DANIEL CHESTER (1850– )
• FRENCH, NICHOLAS (1604-1678)

French into Mammiferes, and replaced in See also:

• GERMAN
• GERMAN, DUTCH AND SCANDINAVIAN

German by the practically See also:

• EQUIVALENT

equivalent See also:

• TERM

term Sdugethiere) has been anglicized into " Mammals " (mammal, in the singular) . Of See also:

• RECENT

recent years, and more especially in See also:

• AMERICA

America, it has become a See also:

• CUSTOM (from O. Fr. costume, costume or coustume; Low Lat. costuma, a shortened form of consuetudo)

custom to designate the study of mammals by the term " mammalogy." Etymologically, how-ever, that designation cannot be justified; for it is of hybrid (Latin and See also:

• GREEK
• GREEK, ETRUSCAN AND

Greek) origin, and is equivalent to " mastology," the See also:

• SCIENCE (Lat. scientia, from scire; to learn, know)

science which deals with the mammary gland (Gr . µaaTO , woman's See also:

• BREAST (a word common to Teutonic languages, cf. the Ger. Brust, possibly connected with an O. Sax. brustian, to bud)

breast), a totally different signification . As regards existing forms of See also:

• LIFE

life, the limitations of the class are perfectly well defined and easy of recognition; for although certain See also:

• GROUPS
• GROUPS, THEORY

groups (not, by the way, whales, which, although excluded in popular estimation from the class, are in all essential respects typical mammals) are exceedingly aberrant, and See also:

• PRESENT

present structural features connecting them with the See also:

• LOWER

lower vertebrate classes, yet they are by See also:

• COMMON

common consent retained in the class to which they are obviously most nearly affiliated by their preponderating characteristics . There is thus at the present See also:

• DAY (O. Eng. dreg, Ger. Tag; according to the New English Dictionary, " in no way related to the Lat. dies")
• DAY, JOHN (1574-1640?)
• DAY, THOMAS (1748-1789)

day a See also:

• GREAT

great See also:

• INTERVAL

interval, unbridged by any connecting links, between mammals and the other classes of vertebrates . Not so, however, when the See also:

• EXTINCT

extinct forms of vertebrate life are taken into See also:

• CONSIDERATION (from Lat. considerare, to look at closely, examine, generally taken to be from con-, and the base seen in sidus, sideris, a star, the word being supposed to be originally an astrological or astronomical term)

consideration, for there is a group of See also:

• REPTILES (Lat. Reptilia, creeping things, from reptilis; ref ere, to creep; Gr. Ep7rety, whence the term " herpetology," for the science dealing with them)

reptiles from the See also:

• EARLY
• EARLY, JUBAL ANDERSON (1816-1894)

early See also:

• PART

part of the Secondary, or Mesozoic See also:

• PERIOD
• PERIOD (Gr. irepioSos, a going or way round, circuit, aepi, round, and &Sis, way, road)

period, some of whose members must have been so intimately related to mammals that, were the whole group fully known, it would clearly be impossible to draw a distinction between See also:

• MAMMALIA (from Lat. mamma, a teat or breast)

Mammalia on the one See also:

• HAND
• HAND (a word common to Teutonic languages; cf. Ger. Hand, Goth. handus)
• HAND, FERDINAND GOTTHELF (1786-185r)

hand and Reptilia on the other . Indeed, as it is, we are already partially acquainted with one of these early intermediate creatures (Tritylodon), which forms a See also:

• KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind of zoological See also:

• SHUTTLE (O. Eng. shitel, &c.; from the same word as " shoot ")

shuttle-See also:

• COCK, EDWARD (1805-1892)

cock, being, so to speak, See also:

• HIT

hit from one group to another, and hack again, by the various zoologists by whom its scanty remains have been studied . Considered collectively, mammals, which did not make their See also:

• APPEARANCE (from Lat. apparere, to appear)

appearance on the See also:

• EARTH
• EARTH (a word common to Teutonic languages, cf. Ger. Erde, Dutch aarde, Swed. and Dan. jord; outside Teutonic it appears only in the Gr. 'pq'e, on the ground; it has been connected by some etymologists with the Aryan root ar-, to plough, which is seen in
• EARTH, FIGURE OF
• EARTH, FIGURE OF THE

earth for some See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time after reptiles had existed, are certainly the highest group of the whole vertebrate sub-See also:

• KINGDOM

kingdom . This expression must not, however, be considered in too restricted a sense . In mammals, as in other classes, there are See also:

• LOW, SETH (1850- )
• LOW, WILL HICOK (1853- )

low as well as high forms; but by any tests that can be applied, especially those based on the See also:

• STATE
• STATE, GREAT OFFICERS OF

state of development of the central See also:

• NERVOUS

nervous See also:

• SYSTEM

system, it will be seen that the See also:

• AVERAGE

average exceeds that of any other class, that many See also:

• SPECIES

species of this class far excel those of any other in perfection of structure, and that it contains one See also:

• FORM (Lat. forma)

form which is unquestionably the culminating point amongst organized beings .

Mammals, then, are vertebrated animals, possessing the normal characteristics of the members of that primary See also:

• DIVISION (from Lat. dividere, to break up into parts, separate)

division of the See also:

• ANIMAL
• ANIMAL (Lat. animalis, from anima, breath, soul)

animal kingdom . They are separated from fishes and batrachians (See also:

• PISCES (the fishes)

Pisces and Batrachians) on the one hand, and agree with reptiles, and birds (Reptilia and Ayes) on the other, in the See also:

• POSSESSION
• POSSESSION (Lat. possessio, possidere, to possess)

possession during See also:

• INTRA

intra-uterine life of the membranous vascular structures respectively known as the amnion and the allantois, and likewise in the See also:

• ABSENCE (Lat. absentia)

absence at this or any other period of See also:

• EXTERNAL

external gills . A four-chambered See also:

• HEART
• HEART, LUNG

heart, with a See also:

• COMPLETE

complete See also:

• DOUBLE
• DOUBLE (from the Mid. Eng. duble, the form which gives the present pronunciation, through the Old Er. duble, from Lat. duplus, twice as much)

double circulation, and warm See also:

• BLOOD

blood (less markedly so in the lowest group than in the See also:

• REST (O. Eng. rest, reste, bed, cognate with other Teutonic forms, e.g. Ger. Rast, Riiste, rest, and probably Gothic Rasta, league, i.e. resting or stopping place)

rest of the class), distinguish mammals from existing reptiles, although not from birds . From both birds and reptiles the class is distinguished, so far at any See also:

• RATE

rate as existing forms are concerned, by the following features: the absence of a See also:

• NUCLEUS (Lat. for the kernal of a nut, nux, the stone of fruit)

nucleus in the red corpuscles of the blood, which are nearly always circular in outline; the See also:

• FREE

free suspension of the lungs in a thoracic cavity, separated from the abdominal cavity by a See also:

• MUSCULAR

muscular See also:

• PARTITION

partition, or See also:

• DIAPHRAGM (Gr. Scat/pay,aa, a partition)

diaphragm, which is the See also:

• CHIEF (from Fr. chef, head, Lat. caput)

chief See also:

• AGENT (from Lat. agere, to act)

agent in inflating the lungs in respiration; the aorta, or See also:

• MAIN (from the Aryan root which appears in " may " and " might," and Lat. magnus, great)
• MAIN (Lat. Moenus)

main artery, forming but a single See also:

• ARCH
• ARCH, JOSEPH (1826– )

arch after leaving the heart, which curves over the leftterminal division of the See also:

• WINDPIPE

windpipe, or bronchus; the presence of more or fewer hairs on the skin and the absence of feathers; the greater development of the See also:

• BRIDGE

bridge, or commissure, connecting the two halves of the See also:

• BRAIN (A.S. braegen)

brain, which usually forms a complete corpus callosum, or displays an unusually large See also:

• SIZE

size of its anterior portion; the presence of a fully See also:

• DEVELOPED

developed larynx at the upper end of the trachea or windpipe, accompanied by the absence of a See also:

• SYRINX (ovpryE)

syrinx, or expansion, near the lower end of the same; the circumstance that each See also:

• HALF

half of the lower See also:

• JAW (Mid. Eng. jawe, jowe and geowe, O. Eng. cheowan, connected with " chaw " and " chew," and in form with " jowl ")

jaw (except perhaps at a very early See also:

• STAGE (Fr. 6/age; from Lat. stare, to stand)

stage of development) consists of a single piece articulating posteriorly with the squamosal See also:

• ELEMENT (Lat. elementum)

element of the See also:

• SKULL

skull without the intervention of a See also:

• SEPARATE

separate quadrate See also:

• BONE (a word common in various forms to Teutonic languages, in many of which it is confined to the shank of the leg, as in the German Bein)
• BONE, HENRY (1755-1834)

bone; the absence of prefrontal bones in the skull; the presence of a pair of lateral knobs, or condyles (in See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place of a single median one), on the occipital aspect of the skull for See also:

• ARTICULATION (from Lat. articulare, to divide into joints)

articulation with the first vertebra; and, lastly, the very obvious See also:

• CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character of the See also:

• FEMALE

female being provided with milk-glands, by the secretion of which the young (produced, except in the very lowest group, alive and not by means of externally hatched eggs) are nourished for some time after See also:

• BIRTH (a word common in various forms to Teutonic languages from the root of the verb " to bear ")

birth . In the See also:

• MAJORITY (Fr. majorite; Med. Lat. majoritas; Lat. major, greater)

majority of mammals both pairs of limbs are well developed and adapted for walking or See also:

• RUNNING

running . The fore-limbs may, however, be modified, as in moles, for burrowing, or, as in bats, for See also:

• FLIGHT

flight, or finally, as in whales and dolphins, for See also:

• SWIMMING (from " swim," A.S. swimman, the root being common in Teutonic languages)

swimming, with the See also:

• ASSUMPTION, FEAST OF

assumption in this latter instance of a ffipper-like form and the complete disappearance of the See also:

• HIND

hind-limbs . Special adaptations for climbing are exhibited by both pairs of limbs in opossums, and for See also:

• HANGING

hanging to boughs in sloths . In no instance are the fore-limbs wanting . In the great majority of mammals the hind extremity of the See also:

• AXIS (Lat. for " axle ")

axis of the See also:

• BODY

body is prolonged into a tail . Very generally the tail has distinctly the appearance of an appendage, but in some of the lower mammals, such as the thylacine among marsupials, and the aard-vark or See also:

• ANT
• ANT (O. Eng. aemete, from Teutonic a, privative, and maitan, cut or bite off, i.e. " the biter off "; aemete in Middle English became differentiated in dialect use to (mete, then amte, and so ant, and also to emete, whence the synonym " emmet," now only u

ant-See also:

• BEAR
• BEAR, BLACK
• BEAR, BROWN
• BEAR, GRIZZLY
• BEAR, ISABELLINE
• BEAR, WHITE

bear among the edentates, it is much thickened at the See also:

• ROOT (late O.E. rot, adopted from Scand., cf. Norw. and Swed. rot, Dan. rod; the true O.E. word was wyrt, plant, represented in Ger. Wurz or Wurzel; the ultimate root is the same in both words, and is seen in Lat. radix)
• ROOT, ELIHU (1845– )

root, and passes insensibly into the body, after the See also:

• FASHION (adapted from Fr. facon, agon, Lat. factio, making, facere, to do or make)

fashion common among reptiles . As regards See also:

• FUNCTION

function, the tail may be a See also:

• MERE
• MERE, ADALBERT (1838-1909)

mere pendent appendage, or may be adapted to grasp boughs in climbing, or even to collect See also:

• FOOD
• FOOD (like the verb " to feed," from a Teutonic root, whence O. Eng. foda; cf. " fodder "; connected with Gr. lrareicOae, to feed)

food or materials for a See also:

• NEST

nest or sleeping place, as in the spider-monkeys, opossums and See also:

• RAT (a word common to Teut. and Rom. languages; probably first adopted in Teut.; the ultimate origin is not known; Skeat suggests the root rad-, to scratch; cf. Ger. Ratte, Dan. rotte, Fr. rat, &c.)

rat-kangaroos . Among See also:

• JUMPING

jumping animals it may serve as a See also:

• BALANCE (derived through the Fr. from the Late Lat. bilantia, an apparatus for weighing, from bi, two, and lanx, a dish or scale)

balance, as in the See also:

• CASE
• CASE, JOHN (d. 1600)

case of jerboas and kangaroos, while in the latter it is also used as a support when resting; among many hoofed mammals it is used as a See also:

• FLY (formed on the root of the supposed original Tent. fleugan, to fly)

fly-whisk; and in whales and dolphins, as well as in the See also:

• AFRICAN

African Potamogale and the See also:

• NORTH
• NORTH, BARONS
• NORTH, MARIANNE (1830—1890)
• NORTH, ROGER (1653-1734)
• NORTH, SIR THOMAS (1535?-16o1?)

North See also:

• AMERICAN

American See also:

• MUSQUASH

musquash, it plays an important part in swimming .

Its supposed use as a See also:

• TROWEL (Med. Eng. truel, O. Fr. truelle, Low Lat. truella, a variant of trulla, diminutive of trua, stirring spoon, ladle, Gr. ropbvrt, from the root tar, to turn round and round; cf. ropebs, borer)

trowel by the See also:

• BEAVER
• BEAVER (from Fr. baviere, a child's bib, from bane, saliva)

beaver is, however, not supported by the actual facts of the case . As already indicated, the limbs of different mammals are specially modified for various modes of life; and in many cases analogous modifications occur, in greater or less degree, through-out the entire body . Those modifications most noticeable in the case of See also:

• CURSORIAL

cursorial types may be briefly mentioned as examples . In this case, as might be expected, the greatest modifications occur in the limbs, but correlated with this is also an See also:

• ELONGATION

elongation of the See also:

• HEAD (in 0. Eng. heafad; the word is common to Teutonic languages; cf. Dutch hoofd, Ger. Haupt, generally taken to be in origin connected with Lat. caput, Gr. KerbOvi7)
• HEAD, SIR EDMUND WALKER, BART
• HEAD, SIR FRANCIS BOND, BART

head and See also:

• NECK (O. Eng. hnecca; the word appears in many Teutonic languages; cf. Dutch ride, Ger. Nacken; in O. E. the common word was heals; cf. Ger. Hals)

neck in See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long-legged types . See also:

• ADAPTATION (from Lat. adaptare. to fit to)

Adaptation for See also:

• SPEED, JOHN (1552–1629)

speed is further exhibited in the moulding of the shape of the body so as to present the minimum amount of resistance to the See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air, as well as in increase in heart and See also:

• LUNG

lung capacity to meet the extra See also:

• EXPENDITURE

expenditure of See also:

• ENERGY (from the Gr. ivipyela; iv, in, ipyov, work)

energy . Finally, in the jumping forms we meet with an increase in the length and See also:

• WEIGHT

weight of the tail, which has to See also:

• ACT (Lat. actus, actum)

act as a counterpoise . As regards the feet, a reduction in the number of digits from the typical five is a frequent feature, more especially among the hoofed mammals, where the See also:

• CULMINATION (from Lat. culmen, summit)

culmination in this respect is attained by the existing members of the See also:

• HORSE (a word common to Teutonic languages in such forms as hors, hros, ros; cf. the Ger. ross)

horse tribe and certain representatives of the extinct See also:

• SOUTH
• SOUTH, ROBERT (1634–1716)

South American Proterotheriidae, both of which are monodactyle . Brief reference may also be made to the morphological importance of extraordinary length or shortness in the skulls of mammals—dolichocephalism and brachycephalism; both these features being apparently characteristic of specialized types, the former See also:

• CONDITION (Lat. condicio, from condicere, to agree upon, arrange; not connected with conditio, from condere, conditum, to put together)

condition being (as in the horse) often, although not invariably, connected with length of See also:

• LIMB

limb and neck, and adaptation to speed, while brachycephalism 'may be correlated with See also:

• SHORT, FRANCIS JOB (1857– )

short limbs and an abbreviated neck . Exceptions to this See also:

• RULE

rule, as exemplified by the See also:

• CATS, JACOB (1577-1660)

cats, are due to special adaptive causes . In point of bodily size mammals present a greater range of variation than is exhibited by any other living terrestrial animals, the extremes in this respect being displayed by the African See also:

• ELEPHANT

elephant on the one hand and certain species of See also:

• SHREW

shrew-mice (whose.head and body scarcely exceed an See also:

• INCH (O. Eng. ynce from Lat. uncia, a twelfthpart; cf. " ounce," and see As)

inch and a half in length) on the other . When the aquatic members of the class are taken into consideration, the maximum dimensions are vastly greater, See also:

• SIBBALD, SIR ROBERT (1641-1722)

Sibbald's See also:

• RORQUAL

rorqual attaining a length of fully 8o ft., and being probably the bulkiest and heaviest animal that has ever existed . Within the limits of individual groups, it may be accepted as a See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

general rule that increase in bulk or stature implies increased specialization; and, further, that the largest representatives of any particular group are also approximately the latest .

The latter dictum must not, however, be pushed to an extreme, since the African elephant, which is the largest living See also:

• LAND

land mammal, attaining in exceptional cases a height approaching 12 ft., was largely exceeded in this respect by an extinct See also:

• INDIAN

Indian species, whose height has been estimated at between rs and r6 ft . In regard to sense-See also:

• ORGANS

organs, ophthalmoscopic observations on the eyes of living mammals (other than See also:

• MAN
• MAN, ISLE OF (anc. Mona)

man) have revealed the existence of great variation in the arrangement of the blood-vessels, as well as in the See also:

• COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour of the retina; See also:

• BLUE (common in different forms to most European languages)

blue and See also:

• VIOLET

violet seem to be unknown, while red, yellow and See also:

• GREEN, A
• GREEN, ALEXANDER HENRY (1832—1896)
• GREEN, DUFF (1791—1875)
• GREEN, JOHN RICHARD (1837—1883)
• GREEN, MATTHEW (1696-1737)
• GREEN, THOMAS HILL (1836-1882)
• GREEN, VALENTINE (1739–1813)
• GREEN, WILLIAM HENRY (.1825–1900)

green form the predominating shades . In the main, the various types of See also:

• MINUTE
• MINUTE (Lat. minutes, small; minuere, to make less)

minute ocular structure correspond very closely to the different groups into which mammals are divided, this See also:

• CORRESPONDENCE
• CORRESPONDENCE (from med. scholastic Lat. correspondentia, corrcspondere, compounded of Lat. cum, with, and respond ere, to answer; cf. Fr. correspondance)

correspondence affording important testimony in the favour of the general correctness of the See also:

• CLASSIFICATION (Lat. classis, a class, probably from the root cal-, cla-, as in Gr. icaMce, clamor)

classification . Among the exceptions are the South American See also:

• SQUIRREL
• SQUIRREL (Fr. ecureuil)

squirrel-monkeys, whose eyes approximate in structure to those of the lemurs . Man and monkeys alone possess parallel and convergent See also:

• VISION (from Lat. videre, to see), or SIGHT

vision of the two eyes, while a divergent, and consequently a very widely extended, vision is a See also:

• PREROGATIVE

prerogative of the lower mammals; squirrels, for instance, and probably also See also:

• HARES

hares and rabbits, being able to see an See also:

• OBJECT

object approaching them directly from behind without turning their heads . An osteological question which has been much discussed is the See also:

• FATE

fate of the reptilian quadrate bone in the mammalian skull . In the See also:

• OPINION (Lat. opinio, from opinari, to think)

opinion of F . W . Thyng, who has carefully reviewed all the other theories, the balance of See also:

• EVIDENCE (Lat. evidentia, evideri, to appear clearly)

evidence tends to show that the quadrate has been taken up into the inner See also:

• EAR (common Teut.; O.E. are, Ger. Ohr, Du. oor, akin to Lat. auris, Gr. ovs)

ear, where it is represented among the auditory ossicles by the incus . Although the present See also:

• ARTICLE (from Lat. articulus, a joint)

article does not discuss mammalian See also:

• OSTEOLOGY (Gr. ovTeov, bone)

osteology in general (for which see See also:

• VERTEBRATA

VERTEBRATA), it is interesting to See also:

• NOTICE

notice in this connexion that the See also:

• PRIMITIVE

primitive condition of the mammalian tympanum apparently consisted merely of a small and incomplete bony See also:

• RING (O.E. hring; a word common to Teutonic languages; and probably cognate with the Lat. circus, Gr. KtpKOS or KpLKOS, Skt'. chakra, wheel, circle, cf. also " harangue "); in art, a band of circular shape of varying sizes, made of any material and used f

ring, with, at most, an imperfect ventral See also:

• WALL (O. Eng. weal, weall, Mid. Eng. wal, wane, adapted from Lat. vallum, rampart; the original O. Eng. word for a wall was wag or tenth)
• WALL, RICHARD (1694-1778)

wall to the tympanic cavity, and that a See also:

• CLOSE
• CLOSE (from Lat. clausum, shut)
• CLOSE, MAXWELL HENRY (1822-1903)

close approximation to this See also:

• ORIGINAL

original condition still persists in the monotremes, especially Ornithorhynchus . The tympano-hyal is the characteristic mammalian element in this region; but the entotympanic likewise appears to be See also:

• PECULIAR

peculiar to the class, and to be unrepresented among the lower vertebrates . The tympanum itself has been regarded as representing one of the elements—probably the supra-angular--of the See also:

• COMPOUND
• COMPOUND (from Lat. componere, to combine or put together)

compound reptilian lower jaw .

The presence of only seven vertebrae in the neck is a very See also:

• CONSTANT, BENJAMIN (1845-1902)

constant feature among mammals; the exceptions being very few . Two other points in connexion with mammalian osteology may be noticed . A large number of mammals possess a perforation, or foramen, on the inner See also:

• SIDE
• SIDE (mod. Eski Adalia)

side of the lower end of the humerus, and also a See also:

• PROJECTION

projection on the See also:

• SHAFT
• SHAFT (O. Eng., sceaft, from scafan, to shave; the word is common to Teutonic languages)

shaft of the femur known as the third trochanter . From its occurrence in so many of the lower vertebrates, the entepicondylar foramen of the humerus, as it is called, is regarded by Dr E . Stromer as a primitive structure, of which the original object was to protect certain nerves and bloodvessels . It is remarkable that it should persist in the spectacled bear of the See also:

• ANDES

Andes, although it has disappeared in all other living members of the group . The third trochanterof the femur, on the other hand, can scarcely be regarded as primitive, seeing that it is absent in several of the lower groups of mammals . Neither can its presence be attributed, as See also:

• PROFESSOR (the Latin noun formed from the verb profiteri, to declare publicly, to acknowledge, profess)

Professor A . See also:

• GAUDRY, JEAN ALBERT (1827-1908)

Gaudry suggests, to the reduction in the number of the toes, as otherwise it should not be found in the See also:

• RHINOCEROS

rhinoceros . Its general absence in man forbids the See also:

• IDEA (Gr. Ibia, connected with i&eiv, to see; cf. Lat. species from specere, to look at)

idea of its having any connexion with the upright posture . See also:

• HAIR (a word common to Teutonic languages)

Hair.—In the greater number of mammals the skin is more or less densely clothed with a peculiarly modified form of epidermis known as hair . This consists of hard, elongated, slender, cylindrical or tapering, See also:

• THREAD (0. Eng. praed, literally, that which is twisted, prawan, to twist, to throw, cf. " throwster," a silk-winder, Ger. drehen, to twist, turn, Du. draad, Ger. Draht, thread, wire)

thread-like masses of epidermic See also:

• TISSUE (Fr. tissu, tissue, participle of tisser, Lat. texere, to weave)

tissue, each of which grows, without branching, from a short prominence, or papilla, sunk at the bottom of a See also:

• PIT (O. E. pytt, cognate with Du. put, Ger. Pfutze, &c., all ultimately adaptations of Lat. puteus, well, formed from root pu-, to cleanse, whence gurus, clean, pure)

pit, or follicle, in the true skin, or dermis .

Such hairs, either upon different parts of the skin of the same species, or in different species, assume very diverse forms and are of various sizes and degrees of rigidity—as seen in the See also:

• FUR (connected with O. Fr. forre, a sheath or case; so " an outer covering ")

fur of the See also:

• MOLE
• MOLE, LOUIS MATHIEU, COMTE (1781—1855)
• MOLE, MATHIEU (1584—1656)

mole, the bristles of the See also:

• PIG
• PIG (a word of obscure origin, connected with the Low Ger. and Dut. word of the same meaning, bigge)

pig, and the spines of the See also:

• HEDGEHOG, or URCHIN

hedgehog and See also:

• PORCUPINE (Fr., pore-epic, " spiny pig ")

porcupine, which are all modifications of the same structures . These See also:

• DIFFERENCES, CALCULUS OF (Theory of Finite Differences)

differences arise mainly from the different arrangement of the constituent elements into which the epidermal cells are modified . Each hair is composed usually of a cellular pithy See also:

• INTERNAL

internal portion, containing much air, and a denser or more horny external or cortical part . In some mammals, as See also:

• DEER (O. E. rigor, dfor, a common Teutonic word, meaning a wild animal, cf. Ger. Tier, Du. dier, &c., probably from a root dhus-, to breathe)
• DEER, CHINESE

deer, the substance of the hair is almost entirely composed of the central medullary or cellular substance, and is consequently very easily broken; in others the horny part prevails almost exclusively, as in the bristles of the See also:

• WILD, JONATHAN (c. 1682-1725)

wild See also:

• BOAR (0. Eng. bar; the word is found only in W. Ger. languages, cf. Dutch beer, Ger. Eber)

boar . In the three-toed See also:

• SLOTH

sloth (Bradypus) the hairs have a central horny axis and a pithy exterior . Though generally nearly smooth, or but slightly scaly, the See also:

• SURFACE

surface of some hairs is imbricated ; that is to say, shows projecting See also:

• SCALE
• SCALE (1) A

scale-like processes, as in some bats, while in the two-toed sloth (Choloepus) they are longitudinally grooved or fluted . Though usually more or less cylindrical or circular in See also:

• SECTION
• SECTION (Lat. sectio, cutting, secare, to cut)

section, hairs are often elliptical or flattened, as in the See also:

• CURLY, JEAN NICOLAS (1774-1827)

curly-haired races of men, the terminal portion of the hair of moles and shrews, and conspicuously in the spines of the spiny squirrels of the genus Xerus and those of the See also:

• MOUSE

mouse-like Platacanthomys . Hair having a See also:

• PROPERTY

property of mutual cohesion or " felting," which depends upon a roughened scaly surface and a tendency to curl, as in domestic See also:

• SHEEP
• SHEEP (from the Anglo-Saxon sceap, a word common in various forms to Teutonic languages; e.g. the German Schaf)

sheep, is called " See also:

• WOOL, WORSTED AND WOOLLEN MANUFACTURES

wool." It has been shown by J . C . H. de Meijere that the insertion of the individual hairs in the skin displays a definite arrangement, constant for each species, but varying in different groups . In jerboas, for example, a bunch of twelve or thirteen hairs springs from the same point, while in the polar bear a single stout hair and several slender ones arise together, and in the marmosets three equal-sized hairs form See also:

• REGULAR

regular groups . These tufts or groups like-See also:

• WISE, HENRY ALEXANDER (1806-1876)
• WISE, ISAAC MAYER (1819-1900)

wise display an orderly and definite grouping in different mammals, which suggests the origin of such groups from the existence in primitive mammals of a scaly coat comparable to that of reptiles, and indeed directly inherited therefrom .

In a large proportion of mammals there exist hairs of two distinct types: the one long, stiff, and alone appearing on the surface, and the other shorter, finer and softer, constituting the under-fur, which may be compared to the down of birds . A well-known example is furnished by the fur-bearing See also:

• SEALS

seals, in which the See also:

• OUTER

outer fur is removed in the manufacture of commercial " See also:

• SEAL
• SEAL, FUR
• SEAL, HAIR

seal-skin," leaving only the soft and See also:

• FINE

fine under-fur . Remarkable differences in the direction or slope of the hair are noticeable on different parts of the body and limbs of many mammals, especially in certain apes, where the hair of the fore-limbs is inclined towards the See also:

• ELBOW

elbow from above and from below . More remarkable still is the fact that the direction of the slope often differs in closely allied groups, as, for instance, in African and See also:

• ASIATIC

Asiatic buffaloes, in which the hair of the See also:

• MIDDLE

middle See also:

• LINE

line of the back has opposite directions . Whorls of hair, as on the See also:

• FACE (from Lat. fades, derived either from facere, to make, or from a root fa-, meaning " appear "; cf. Gr. cbatvstv)

face of the horse and the South American deer known as brockets, occur where the different hair-slopes meet . In this connexion reference may be made to patches or lines of long and generally See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white hairs situated on the back of certain ruminants, which are capable of erection during periods of excitement, and serve, apparently, as " flags " to See also:

• GUIDE (in Mid. Eng. gyde, from the Fr. guide; the earlier French form was guie, English " guy," the d was due to the Italian form guida; the ultimate origin is probably Teutonic, the word being connected with the base seen in O. Eng. witan, to know)

guide the members of a See also:

• HERD (a word common to Teutonic languages; the O. Eng. form was heord; cf. Ger. Herde, Swed. and Dan. hjord; the Sans. ca'rdhas, which shows the pre-Teutonic form, means a troop)

herd in flight . Such are the white chrysanthemum-like patches on the rump of the See also:

• JAPANESE

Japanese deer and of the American prong-See also:

• BUCK
• BUCK, CARL DARLING (1866– )
• BUCK, DUDLEY (1839-1909)

buck (Antilocapra), and the line of hairs situated in a groove on the loins of the African See also:

• SPRING (from " to spring," " to leap or jump up," " burst out," O. Eng., springau, a common Teut. word, cf. Ger. springer, possibly allied to Gr. QnrFpxecOac, to move rapidly)

spring-buck . The white under-side of the tail of the See also:

• RABBIT

rabbit and the yellow rump-patch of many deer are analogous . The See also:

• EYE
• EYE (O. Eng. edge, Ger. Auge; derived from an Indo-European root also seen in Lat. oc-ulus, the organ of vision (q.v.)

eye-lashes, or ciliae, are See also:

• FAMILIAR (through the Fr. familier, from Lat. familiaris, of or belonging to the familia, family)

familiar examples of a special See also:

• LOCAL

local development of hair . Special tufts of stout stiff hairs, sometimes termed vibrissae, and connected with nerves, and in certain cases with glands, occur in various regions . They are most common on the head, while they constitute the " whiskers," or " feelers," of the cats and many rodents . In other instances, notably in the lemurs, but also in certain See also:

• CARNIVORA

carnivora, rodents and marsupials, they occupy a position on the fore-See also:

• ARM (a common Teutonic word; the Indo-European root is ar, to join or fit; cf. the Lat. armus, shoulder, and the plural word arma, weapons, Gr. apphs, joint, and the reduplicated apapilKSV, to join)

arm near the See also:

• WRIST

wrist, in connexion with glands, and receive sensory See also:

• POWERS, HIRAM (1805-1873)

powers from the radial See also:

• NERVE (Lat. nervus, Gr. vevpov, a bowstring)

nerve .

In some mammals the hairy covering is partial and limited to particular regions; in others, as the See also:

• HIPPOPOTAMUS (" river-horse," Gr. lames, horse and aoraµbs, river)

hippopotamus and the See also:

• SEA (in O. Eng. sae, a common Teutonic word; cf. Ger. See, Dutch Zee, &c.; the ultimate source is uncertain)
• SEA, COMMAND OF THE

sea-cows, or Sirenia, though scattered over the whole surface, it is extremely short and scanty; but in none is it reduced to so great an extent as in the See also:

• CETACEA
• CETACEA (from the Gr. ,Eros, a whale)

Cetacea, in which it is limited to a few small bristles confined to the See also:

• NEIGHBOUR (O. Eng. neahgebiir, from Walt, " nigh," " near ")

neighbour-See also:

• HOOD,
• HOOD, JOHN BELL (1831–1879)
• HOOD, SAMUEL HOOD, VISCOUNT (1724–1816)
• HOOD, SIR SAMUEL (1762-1814)
• HOOD, THOMAS (1799-1845)
• HOOD, TOM (1835–1874)

hood of the lips and nostrils, and often present only in the young, or even the foetal condition . Some kinds of hairs, as those of the mane and tail of the horse, persist throughout life, but more generally, as in the case of the body-hair of the same animal, they are See also:

• SHED

shed and renewed periodically, generally annually . Many mammals have a longer hairy coat in See also:

• WINTER, JOHN STRANGE
• WINTER, PETER (c. 1755-1825)

winter, which is shed as summer conies on; and some few, which inhabit countries covered in winter with See also:

• SNOW (in O. Eng. sndw; a common Indo-European word; cf. in Teutonic languages, Ger. Schnee, Du. sneeuw; in Slavonic snieg', Lith. snegas; Gr. vi4a, Lat. nix, nivis, whence the Romanic forms, Ital. neve, Fr. neige, &c.; Ir. and Gael. sneachd; the original

snow, as the See also:

• ARCTIC (Gr. "ApKroc, the Bear, the northern constellation of Ursa Major)

Arctic See also:

• FOX
• FOX, C
• FOX, CHARLES JAMES (1749-1806)
• FOX, EDWARD (c. 1496-1538)
• FOX, GEORGE (1624-1691)
• FOX, RICHARD (c. 1448-1528)
• FOX, ROBERT WERE (1789—1877)
• FOX, SIR STEPHEN (1627–1716)
• FOX, SIR WILLIAM (1812-1893)

fox, variable See also:

• HARE
• HARE, SIR JOHN (1844– )

hare and See also:

• ERMINE

ermine, undergo a complete See also:

• CHANGE (derived through the Fr. from the Late Lat. cambium, cambiare, to barter; the ultimate derivation is probably from the root which appears in the Gr. «a urmu', to bend)

change of colour in the two seasons, being white in winter and See also:

• GREY, CHARLES GREY, 2ND EARL (1764-1845)
• GREY, HENRY GREY, 3RD EARL (1802-1894)
• GREY, LADY JANE (1537-1554)
• GREY, SIR EDWARD
• GREY, SIR GEORGE (1812–1898)

grey or See also:

• BROWN
• BROWN, CHARLES BROCKDEN (1771-181o)
• BROWN, FORD MADOX (1821-1893)
• BROWN, FRANCIS (1849- )
• BROWN, GEORGE (1818-188o)
• BROWN, HENRY KIRKE (1814-1886)
• BROWN, JACOB (1775–1828)
• BROWN, JOHN (1715–1766)
• BROWN, JOHN (1722-1787)
• BROWN, JOHN (1735–1788)
• BROWN, JOHN (1784–1858)
• BROWN, JOHN (1800-1859)
• BROWN, JOHN (1810—1882)
• BROWN, JOHN GEORGE (1831— )
• BROWN, ROBERT (1773-1858)
• BROWN, SAMUEL MORISON (1817—1856)
• BROWN, SIR GEORGE (1790-1865)
• BROWN, SIR JOHN (1816-1896)
• BROWN, SIR WILLIAM, BART
• BROWN, THOMAS (1663-1704)
• BROWN, THOMAS (1778-1820)
• BROWN, THOMAS EDWARD (1830-1897)
• BROWN, WILLIAM LAURENCE (1755–1830)

brown in summer . There has been much discussion as to whether this winter whitening is due to a change in the colour of the individual hairs or to a change of coat . It has, however, been demonstrated that the senile whitening of human hair is due to the presence of phagocytes, which devour the pigment-bodies; and from microscopic observations recently made by the French naturalist Dr E . Trouessart, it appears that much the same kind of See also:

• ACTION

action takes place in the hairs of mammals that turn white in winter . See also:

• COLD (in O. Eng. cald and ceald, a word coming ultimately from a root cognate with the Lat. gelu, gelidus, and common in the Teutonic languages, which usually have two distinct forms for the substantive and the adjective, cf. Ger. Kolte, kalt, Dutch koude

Cold, by some means or other, causes the pigment-bodies to shift from the normal positions, and to See also:

• TRANSFER (from Lat. transferre, to bear across, carry over)

transfer themselves to other layers of the hair, where they are attacked and devoured by phagocytes . The winter whitening of mammals is, therefore, precisely similar to the senile See also:

• BLEACHING

bleaching of human hair, no shift of the coat taking place . Under the See also:

• INFLUENCE (Late Lat. influentia, from influere, to flow in)

influence of exposure to intense cold a small mammal has been observed to turn white in a single See also:

• NIGHT

night, just as the human hair has been known to blanch suddenly under the influence of intense emotion, and in both cases extreme activity of the phagocytes is apparently the inducing cause . The African See also:

• GOLDEN

golden-moles (Chrysochloris), the desmans or See also:

• WATER

water-moles (Myogale), and the See also:

• WEST
• WEST, BENJAMIN (1738-1820)
• WEST, NICHOLAS (1461-1533)

West African Potamogale velox, are remarkable as being the only mammals whose hair reflects those iridescent tints so common in the feathers of tropical birds . The See also:

• PRINCIPAL

principal and most obvious purpose of the hairy covering is to protect the skin . Its function in the hairless Cetacea is discharged by the specially modified and thickened layer of fatty tissue beneath the skin known as " blubber." Scales, &c.—True scales, or See also:

• FLAT (a modification of O. Eng. flet, an obsolete word of Teutonic origin, meaning the ground beneath the feet)

flat imbricated plates of horny material, covering the greater part of the body, are found in one See also:

• FAMILY

family only of mammals, the pangolins or Manidae; but these are also associated with hairs growing from the intervals between the scales or on the parts of the skin not covered by them .

Similarly imbricated epidermic productions form the covering of the under-surface of the tail of the African flying rodents of the family Anomaluridae; and flat scutes, with the edges in apposition, and not over-laid, clothe both surfaces of the tail of the beaver, rats and certain other members of the rodent See also:

• ORDER
• ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
• ORDER, HOLY

order, and also of some insectivora and marsupials . Armadillos alone possess an external bony See also:

• SKELETON

skeleton, composed of plates of bony tissue, developed in the skin and covered with scutes of horny epidermis: Other epidermic appendages are the horns of ruminants and rhinoceroses—the former being elongated, tapering, hollow caps of hardened epidermis of fibrous structure, fitting on and growing from conical projections of the frontal bones and always arranged in pairs, while the latter are of similar structure, but without any internal bony support, and situated in the middle line . Callosities, or See also:

• BARE

bare patches covered with hardened and thickened epidermis, are found on the buttocks of many apes, the breast of camels, the inner side of the limbs of See also:

• EQUIDAE

Equidae, the grasping under-surface of the tail of prehensile-tailed monkeys, opossums, &c . The greater part of the skin of the one-horned Asiatic rhinoceros is immensely thickened and stiffened by an increase of the tissue of both the skin and epidermis, constituting the well-known jointed " See also:

• ARMOUR, PHILIP DANFORTH (1832-1901)

armour-plated " hide of those animals . Nails, Claws and Hoofs.—With few exceptions, the terminal extremities of the digits of both limbs of mammals are more or less protected or armed by epidermic plates or sheaths, constituting the various forms of nails, claws or hoofs . These are absent in the Cetacea alone . A perforated See also:

• SPUR (A.S. spura, spora, related to spornan, spurnan, to kick, spurn; cf. M.H.G. sporn, mod. Ger. Sporn)

spur, with a special secreting gland in connexion with it, is found attached to each hind-See also:

• LEG
• LEG (a word of Scandinavian origin, from the Old Norwegian leggr, cf. Swed. lagg, Dan. laeg; the O. Eng. word was sceanca, shank)

leg of the See also:

• MALES

males of the existing species of See also:

• MONOTREMATA (a name referring to the single outlet for all the excretory channels of the body)

Monotremata . See also:

• SCENT

Scent-glands, &c.—Besides the universally distributed sweat-glands connected with the hair-system, most mammals have special glands in modified portions of the skin, often involuted to form a shallow See also:

• RECESS (Lat. recessus, a going back, withdrawal, from recedere, to withdraw)

recess or a deep See also:

• SAC

sac with a narrow opening, situated in various parts of the surface of the body, and secreting odorous substances, by the aid of which individuals recognize one another . These probably afford the principal means by which wild animals are able to become aware of the presence of other members of the species, even at great distances . To this group of structures belong the suborbital face-gland, " larmier," or " crumen," of antelopes and deer, the, frontal gland of the muntjak and of bats of the genus Phyllorhina, the See also:

• CHIN

chin-gland of the chevrotains and of Taphozous and certain other bats, the glandular patch behind the ear of the See also:

• CHAMOIS

chamois and the See also:

• REED
• REED, ANDREW (1787-1862)
• REED, ISAAC (1742—1807)
• REED, JOSEPH (1741—1785)
• REED, THOMAS BRACKETT (1839—1902)

reed-buck, the glands on the lower parts of the legs of most deer and a few antelopes (the position of which is indicated by tufts of long and often specially coloured hair), the interdigital See also:

• FOOT

foot-glands of goats, sheep, and many other ruminants, the temporal gland of elephants, the lateral glands of the See also:

• MUSK (Med. Lat. muscus, late Gr. µbvXos, possibly Pers. mushk, from Sansk. mushka, the scrotum)

musk-shrew, the gland on theback of the hyrax and the See also:

• PECCARY

peccary (from the presence of which the latter animal takes the name Dicotyles), the gland on the tails of the members of the See also:

• DOG

dog-tribe, the preputial glands of the musk-deer and beaver (both well known for the use made of their See also:

• POWER [WILLIAM GRATTAN] TYRONE (1797-1841)

power-fully odorous secretion in See also:

• PERFUMERY (Lat. per, through, and fumare, to smoke)

perfumery), and also of the See also:

• SWINE

swine and hare, the anal glands of Carnivora, the perineal gland of the See also:

• CIVET

civet (also of commercial value), the caudal glands of the fox and See also:

• GOAT (a common Teut. word; O. Eng. gat, Goth. gaits, Mod. Ger. Geiss, cognate with Lat. haedus, a kid)

goat, the gland on the wing-membrane of bats of the genus Saccopteryx, the See also:

• POST

post-digital gland of the rhinoceros, &c . Very generally these glands are common to both sexes, and it is in such cases that their function as a means of mutual recognition is most evident . It has been suggested that the above-mentioned callosities or " chestnuts " on the limbs of horses are vestigial scent-glands; and it is See also:

• NOTE
• NOTE (Lat. nota, mark, sign, from noscere, to know)

note-worthy that scrapings or shavings from their surface have a powerful attraction for other horses, and are also used by poachers and burglars to keep See also:

• DOGS, ISLE OF

dogs silent .

The position of such glands on the lower portions of the limbs is plainly favourable to a recognition-taint being See also:

• LEFT

left in the tracks of terrestrial animals; and antelopes have been observed deliberately to rub the secretion from their face-glands on See also:

• TREE (0. Eng. treo, treow, cf. Dan. tree, Swed. Odd, tree, trd, timber; allied forms are found in Russ. drevo, Gr. opus, oak, and 36pv, spear, Welsh derw, Irish darog, oak, and Skr. dare, wood)
• TREE, SIR HERBERT BEERBOHM (1853- )

tree-trunks . When glands are confined to the male, their function is no doubt sexual; the secretion forming part of the attraction, or stimulus, to the other See also:

• SEX (Lat. sexes; possibly connected with secure, to cut)

sex . Dentition.—In the great majority of mammals the See also:

• TEETH (O.E. Eel); plural of tooth, O.E. top)

teeth form a definite See also:

• SERIES (a Latin word from serere, to join)

series, of which the hinder elements are of a more or less complex type, while those in front are simpler . With the exception of the marsupials, a set of See also:

• DECIDUOUS (from Lat. decidere, to fall down)

deciduous, or milk, teeth is developed in most mammals with a complicated type of dentition; these milk-teeth being shed at a comparatively early period (occasionally even in utero), when they are succeeded by the larger permanent series, which is the only other ever developed . This double series of teeth thus forms a very characteristic feature of mammals generally . Both the milk and the permanent dentition display the aforesaid complexity of the hinder teeth as compared with those in front, and since the number of milk-teeth is always considerably less than that of the permanent set, it follows that the hinder milk-teeth are usually more complex than the teeth of which they are the predecessors in the permanent series, and represent functionally, not their immediate successors, but those more posterior permanent teeth which have no See also:

• DIRECT

direct predecessors . This character is clearly seen in those animals in which the various members of the lateral or cheek series are well differentiated from each other in form, as the Carnivora, and also in man . In mammals with two sets of teeth the number of those of the permanent series preceded by milk-teeth varies greatly, being sometimes, as in marsupials and some rodents, as few as one on each side of each jaw, and in other cases including the larger portion of the series . As a rule, the teeth of the two sides of the jaws are alike in number and character, except in cases of accidental or abnormal variation, and in the tusks of the See also:

• NARWHAL

narwhal, in which the left is of immense size, and the right rudimentary . In mammals, such as dolphins and some armadillos, which have a large series of similar teeth, not always constant in number in different individuals, there may indeed be differences in the two sides; but, apart from these in describing the dentition of any mammal, it is generally sufficient to give the number and characters of the teeth of one side only . As the teeth of the upper and the lower jaws See also:

• WORK

work against each other in masticating, there is a general correspondence or See also:

• HARMONY (Gr. dpµovia, a concord of musical sounds, dpA'ew to join; &plan midi (sc. TeXvil)

harmony between them, the projections of one series, when the mouth is closed, fitting into corresponding depressions of the other . There is also a general resemblance in the number, characters and mode of See also:

• SUCCESSION (Lat. successio, from succedere, to follow after)

succession of both series; so that, although individual teeth of the upper and lower jaws may not be in the strict sense of the term homologous parts, there is a great convenience in applying the same descriptive terms to the one which are used for the other .

The simplest dentition is that of many species of See also:

• DOLPHIN

dolphin (fig . I), in which the crowns are single-pointed, slightly curved cones, and the roots also single and tapering; so that all the teeth are alike in form from the anterior to the posterior end of the series, though it may be with some slight difference in size, those at the two extremities being rather smaller than the others . Such a dentition is called " homoeodont " (Gr . Snows, like, 6801n, tooth), and in the case cited, as the teeth are never changed, it is also monophyodont (Gr . µboor, alone, single, Obey, to generate, Mobs, tooth) . Such teeth are, adapted only for catching slippery living prev. like See also:

• FISH (O. Eng. fist, a word common to Teutonic languages, cf. Dutch visch, Ger. Fisch, Goth. fisks, cognate with the Lat. piscis)
• FISH, HAMILTON (1808-1893)

fish . fiserlertsf, 11l,1 llllll/l 1 )al'! i.~.r I`ll In a very large number of mammals the teeth of different parts of the series are more or less differentiated in character; and, accordingly, have different functions to perform . The front teeth are See also:

• SIMPLE

simple and one-rooted, and are adapted for cutting and seizing . They are called " incisors." The back, lateral or cheek teeth, on the other hand, have broader and more complex crowns, tuberculated or ridged, and supported on two or more roots . They crush or grind the food, and are hence called " molars." Many mammals have, between these two sets, a tooth at each corner of the mouth, longer and more pointed than the others, adapted for tearing or stabbing, or for fixing struggling See also:

• PREY (0. Fr. preie, mod. proie, Lat. praeda, booty, from prae and the root hed—seen in prehendere, prendere, to grasp)

prey . From the conspicuous development of such teeth in the Carnivora, especially the dogs, they have received the name of " canines." A dentition with its component parts so differently formed that these distinctive terms are applicable to them is called heterodont (Gr. grepos, different) . In most cases, though by no means invariably, mammals with a heterodont dentition are also diphyodont (Gr .

Sufnnis, of double form) . This general arrangement is obvious in a considerable number of mammals; and examination shows that, under great modifications in detail, there is a remarkable uniformity of essential characters in the dentition of a large number of members of the class belonging to different orders and not otherwise closely allied, so much that it C I is possible to formulate a common See also:

• PLAN
• PLAN (from Lat. planes, flat)

plan of dentition from which the others have been derived by the alteration of some and the suppression of other members of the series, and occasionally, but very rarely, by addition . In this generalized form of mammali