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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. 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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