^ 2 LAMELMBRANCHIATA. 



Also on the S. coast of Iceland at: 



63°05' N. L,., 20°7' W. L 293 fin. Numerous spec. 



62°57' I 9°58' - 5°° - 12 spec. & 23 valves. 



Faeroes. 

 P. groenlandicus has been taken off the islands at: 



63°i5' N. L., 9 35' VY. h 270 fm. 2 spec. 



3°°3' ~~ 9° 2 ^' — 2 75 " 1 — & 4 valves. 



6l0l 5' 9°35' c a- 475 - ca - ^o s P ec - 



<u 7' 9°3 ' 44° ~ IO S P CC - & z 9 valves. 



Distribution. Pecten groenlandicus occurs further at Spitzbergen (30— 260 fm., Norweg. North- 

 Atlantic Exped. and others), Fiumarken (30 — 150 fm., Sars), in the Barents Sea (7—250 fm., "Will. 

 Barents") and the Kara Sea (5 — 125 fm., "Dijmphna", Leche) as also in the Siberia Sea as far as to 

 n6 c E. L. (15 — 36 fm., "Vega"). It has not been met with in the Bering Sea, and it is therefore doubt- 

 fully circumpolar. On the other hand, it occurs in the arctic seas N. of America, in the western part 

 of Davis Strait, as well as off Newfoundland (130— 224 fm., Verrill). In high-northern seas it is one 

 of the most frequent Molluscs and occurs in such incredible numbers, that the trawl can take it sometimes 

 by hundredweights (cf. Krause, Mollusken von Ostspitzbergen, Zool. Jahrb. Abth. f. Syst. 6. Bd., p 341). 



Apart from its arctic distribution P. groenlandicus has also another, in the Atlantic. As shown 

 above, it has been taken in the Atlantic S. of Iceland and S. of the Faeroes; Jeffreys records it from 

 the waters N. of the Hebrides (542 fm.), W. and S. of Ireland (257 — 517 fm., "Lightning" and "Porcu- 

 pine"); the "Thor" has taken it off the Channel (625- 670 fm.), the "Caudan" in the Bay of Biscay 

 (500 and 740 fm.), the "Travailleur" and "Talisman" also in the Bay of Biscay (365 — 610 fm.) and N. of 

 vSpain (570 — 625 fm.), the "Josephine" between the Azores and Gibraltar (550 fm.), the "Travailleur" and 

 "Talisman" W. of Morocco and W. of Soudan (410 — 05 fm.). 



Remarks. In high-northern regions P. groenlandicus reaches a considerable size; at E.Green- 

 land, we have heard, it becomes up to 28.5 mm . long, at Jan Mayen 22 mm ., in the Kara Sea 28 mm . 1 ), at 

 Spitzbergen even 32.5 " ,m . 2 ). In comparison with these sizes all my specimens from the true Atlantic 

 are very small; the largest is only 10.75""". I believe therefore, that the P. groenlandicus living in the 

 Atlantic is a dwarf-form. With this agrees also Locard's remark regarding the specimens taken by the 

 "Travailleur-Talisman", that they belong to a var. minor*) and Jeffreys' statement that the specimens 

 taken by the "Porcupine" Exped. off the British Isles were "young only" 4); I believe, that the species in 

 the warm Atlantic is already full-grown at a size, which in the Polar Sea would still be considered young. 



As it is still constantly stated, that the left valve is considerably larger than the right, I may 

 say J.Collin is perfectly right when he writes (I.e., p. 452): "in most .... the valves are of the same 



'I Collin has introduced the term var. major fur specimens from the Kara Sea; Dijmphna-Togtets Zool.-bot. Ud- 

 li\ ite, [886, p. 152. 



X. Knipowitsch: Zool. Ergebn. d. russ. Exped. nach Spitzbergen. Moll, und Brachiop. I, p. 79; Ann. Mus. Zool. 

 Pi tersbourg, T. VI, 1901 



Exped scient <lu Travailleur et du Talisman; Moll. Test. II, 1898, p. 399. 

 4) Proc. Zool. Soe., iSyy, p. 560. 



