LAMPREY  , a

fish belonging to the family Petromyzontidae (from 7rETpos and Ate, literally, stone-suckers), which with the hag-fishes or Myxinidae forms a distinct subclass of fishes, the Cyclostomata, distinguished by the low organization of their skeleton, which is cartilaginous, without vertebral segmentation, without ribs or real jaws, and without limbs . The lampreys are readily recognized by their long, eel-like, scaleless body, terminating anteriorly in the circular, suctorial mouth characteristic of the whole sub-class . On each side, behind the head, there is a row of seven branchial openings, through which the water is conveyed to and from the gills . By means of their mouth they fasten to stones, boats, &c., as well as to other fishes, their object being to obtain a resting-place on the former, whilst they attach themselves to the latter to derive nourishment from them . The inner surface of their cup-shaped mouth is armed with pointed teeth, with which they perforate the integuments of the fish attacked, scraping off particles of the flesh and sucking the blood . Mackerel, cod, pollack and flat-fishes are the kinds most frequently attacked by them in the sea; of river-fish the migratory Salmonidae and the shad are some-times found with the marks of the teeth of the lamprey, or with the fish actually attached to them . About fifteen species are known from the coasts and rivers of the temperate regions of the northern and southern hemispheres . In Great Britain and Europe generally three species occur, viz, the large spotted sea-lamprey (Petromyzon marinus), the river-lamprey or lampern (P. fuviatilis), and the small lampern or " pride " or " sand-piper " (P. branchialis) . The first two are migratory, entering rivers in the spring to spawn; of the river-lamprey, however, specimens are met with in fresh water all the year round . In North America about ten species of lamprey occur, while in South America and Australasia still others are found . Lampreys, especially the sea-lamprey, are esteemed as food, formerly more so than at present; but their flesh is not easy of digestion . Henry I. of England is said to have fallen a victim to this, his favourite dish .

The species of greatest use is the river-lamprey, which as bait is preferred to all others in the cod and turbot

fisheries of the North Sea . Yarrell states that formerly the Thames alone supplied from 1,000,000 to 1,200,000 lamperns annually, but their number has so much fallen off that, for instance, in 1876 only 40,000 were sold to the cod-fishers . That year, however, was an unusually bad year; the lamperns, from their scarcity, fetched £8, sos. a thousand, whilst in ordinary years £5 is considered a fair price . The season for catching 'amperns closes in the Thames about the middle of March . The origin of the name lamprey is obscure; it is an adaptation of Fr. lamproie, Med . Lat. lampreda; this has been taken as a variant of another Med . Lat. form Lampetra, which occurs in ichthyological works of the middle ages; the derivation from lambere petras, to lick stones, is a specimen of etymological ingenuity . The development of lampreys has received much attention on the part of naturalists, since Aug . Muller discovered that they undergo a metamorphosis, and that the minute worm-like lamperns previously known under the name of Ammocoetes, and abundant in the sand and mud of many streams, were nothing but the undeveloped young of the river-lampreys and small lamperns . See CYCLOSTOMATA .