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HAPARANDA (Finnish Haaparanta, " Aspe...

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Originally appearing in Volume V12, Page 933 of the 1911 Encyclopedia Britannica.
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HAPARANDA (Finnish Haaparanta, " See also:Aspen See also:Shore ")  , a See also:town of See also:Sweden in the See also:district (lan) of Norbotten, at the See also:head of the Gulf of See also:Bothnia . Pop . (2goo) 1568 . It lies about 12 m. from the mouth of the Tonne See also:river, on the frontier with See also:Russia (See also:Finland), opposite the town of Tornea which has belonged to Russia since 'Soo . The towns are divided by a marshy channel, formerly the See also:bed of the Tonne, but the See also:main stream is now See also:east of the See also:Russian town . See also:Haparanda was founded in 1812, and at first See also:bore the name of Karljohannstad . It received its municipal constitution in 1842 . See also:Shipbuilding is prosecuted . See also:Sea-going vessels load and unload at Salmio, 7 M. from Haparanda . Since 1858 the town has been the seat of an important meteorological station . See also:Annual mean temperature, 32.4° Fahr.; See also:February 1o•5°; See also:July 58.8° . Rainfall, 16.5 in. annually .

Up the Tonne valley (54 m.) is the See also:

hill Avasaxa, whither pilgrimages were formerly made in See also:order to stand in the See also:light of the See also:sun at midnight on St See also:John's See also:day (See also:June 24) . live in See also:sand, but while the former moves by means of the contraction of its See also:body-See also:wall muscles, Protodrilus can progress by the See also:action of the bands of See also:cilia surrounding its segments, and of the See also:longitudinal ciliated ventral groove . Saccocirrus, which also lives in sand, and more closely resembles the See also:Polychaeta, has throughout the greater length of its body on each segment a pair of small uniramous parapodia bearing a bunch of See also:simple setae . No other member of the See also:group is known to have any trace of setae or parapodia at any See also:stage of development . These three genera have the following characters in See also:common . The body is composed of a large number of segments; the prostomium bears a pair of tentacles; the See also:nervous See also:system consists of a See also:brain and longitudinal ventral See also:nerve cords closely connected with the epidermis (without distinct ganglia), widely separated in Saccocirrus, closely approximated in Protodrilus, fused together in Polygordius; the coelom is well See also:developed, the septa are distinct, and the dorsal and ventral longitudinal mesenteries are See also:complete ; the nephridia are simple, and open into the coelom . Polygordius differs from Protodrilus and Saccocirrus in the See also:absence of a distinct suboesophageal See also:muscular pouch, and in the absence of a See also:peculiar closed cavity in the head region, which is especially well developed in Saccocirrus, and probably represents the specialized coelom of the first segment . Moreover, in Saccocirrus the genital See also:organs, .4 s/pesne - sae SArrxnezaeea, See also:present in the See also:majority of the See also:trunk segments, have become much complicated (fig . 2) . In the See also:female there is in every fertile segment a pair of spermathecae opening at the nephridiopores . In the male there are a right and a See also:left protrusible penis in every genital segment, into which opens the nephridium and a sperm-See also:sac . The wide funnels of the nephridia of this region are possibly of coelomic origin .

Dinophilus is a See also:

free-See also:swimming See also:form without tentacles, and with segmental bands of cilia (fig . I) . The parasitic Histriodritus (Histriobdella) feeds on the eggs of the See also:lobster . It resembles Dinophilus in the See also:possession of a ventral pharyngeal pouch (which bears See also:teeth in Histriodrilus only), the small number of segments, and absence of distinct septa, the absence of a vascular system, the presence of distinct ganglia on the ventral nerve cords, and of small nephridia which do not appear• to open internally . Histriodrilus resembles Saccocirrus in the possession of two posterior adhesive processes, and to some extent in the structure of the complex genital organs, which, however, are restricted to a single segment . In Dinophilua there is also only a single pair of genital ducts behind ; and In the male there are sperm-sacs and a median penis . In some See also:species of Dinophilus there is pronounced sexual dimorphism (the male being small.and without gut) as in the See also:Rotifera . The resemblance of Dinophilus to the Rotifera is, however, quite superficial, and the See also:general structure of this genus with distinct traces of segmentation, especially in the embryo, points to its See also:close See also:affinity, if not to Polygordius in particular, at all events to the See also:Annelida . That Polygordius, Protodrilus and Saccocirrus are on the whole See also:primitive forms, and related to each other, there can be little doubt, but their See also:place amongst the Annelida is difficult to deter-mine . The development of Polygordius alone is well known, having been studied by Hatschek, Fraipont and others . The larva (fig . I, C and D) is a typical but very specialized form of trochophore, provided with a branching nephridium bearing solenocytes .

The trunk develops on the See also:

lower See also:surface of the disk-like larva, which undergoes a more or less sudden See also:metamorphosis into the See also:young See also:worm (fig . I) . There appears to be little either in the development or in the structure of the See also:Haplodrili to See also:warrant the view held by Hatschek and Fraipont that Polygordius and Protodrilus are exceedingly primitive forms, ancestral to the whole group of seta-bearing Annelids (See also:Oligochaeta, Polychaeta, Hirudinea and See also:Echiuroidea) .

End of Article: HAPARANDA (Finnish Haaparanta, " Aspen Shore ")
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