AncTic rpwOvrs'CE. 57 



I. Arctic PEOvrtrcE. 



The NortL. Polar Seas contain but one assemblage of MoUusca, 

 whoso Southern limit is formed by the Aleutian Islands in the 

 PacijSc, but in the North Atlantic is determined chiefly by the 

 boundary of floating ice, descending as low as Newfoundland 

 on the West, and thence rising rapidly to Iceland and the North 

 Cape. A very complete general account of the Arctic Mollusca 

 is given by Dr. Middendorff ;* those of Greenland have been 

 catalogued and described by Otho Fabricius and Holler ;t and 

 more recently by Morch ;J 158 species are enumerated by 

 Middendorff, and 202 by Morch. Scattered notices occur in 

 the Annals of Natural History, § and the Supplements to the 

 Narratives of the Arctic Yoy a gers, — Phipps, Scoresby, Franklin, 

 Back, Eoss, Parry, and Eichardson. The existence of the same 

 marine animals in the Kamtchatka Sea and Baffin's Bay was 

 long since held to prove at least a former North-West passage ; 

 but the occurrence of recent sea-shells in banks far inland 

 rendered it probable that even recent elevation of the land in 

 Arctic America might have much reduced the passage. During 

 the " Glacial period," this Arctic Sea, with the same fauna, ex- 

 tended over Britain ; over Northern Europe, as far as the Alps 

 and Carpathians ; and over Siberia, and a considerable part of 

 North America. The shells now living in the Arctic Seas, are 

 found fossil in the deposits of " Northern Drift," over all these 

 countries ; and a few of the sjoecies yet linger within the bounds 

 of the two next provinces, especially in tracts of unusual depth. 

 The Arctic shells have mostly a thick greenish epidermis (p. 33) ; 

 they occur in very great abundance, and are remarkably subject 

 to variation of form, a circumstance attributed by Professor E. 

 Forbes to the influence of the mixture of fresh water produced 

 by the melting of great bodies of snow and ice. 



ARCTIC SHELL-FISH. 

 R. Russian Lapland. F. Finmark. I. Iceland. G. Greenland. D. Davis Straits (west 

 coast). B. Behring'3 Straits. O. Ochotsk. * British, species (liAiiig). ** British 

 species (fossil). 



Octopus grannlatus. G. 

 Cirroteuthis Miilleri. G. 

 Rossia palpebrosa. G. P. Regent Inlet. 

 Onychotetithis Bergii. F. E. 

 „ Fabricii. G. 



„ amoena. G. 



♦Ommastrephes todams. F. Ncwf. 



Limacina arctic;i. G. 0. 



* Malaco-zoologia Rossica ; Mem. deP Acad. Imp. des Sc. Petersb. T. G, pt. 2, 1S49. 

 t Index Mollusconim Groenlandiffi. Hafn. 1S42. 



t Fortegnelse over Grcinlands Bliiddyr in H. Rink : Grtiulaud geographisk og statia- 

 tisk beskrevet, ii. Bind, 1?57. 

 J Hancock, .A.n. Nat. Hist. voL 18, p. 323, pi. 5. 



