70 NILS ODHNER, NORTHERN AND ARCTIC INVERTEBRATES. V. PROSOBRANCHIA. 1 DIOTOCARDIA. 



the umbilical keels are 2 in number, but a feebler intermedial one may occur; sometimes 

 the keels show a tendency to bipartition by the presence of impressed lines; in general 

 a few feeble angular keels occur, one sometimes stronger than the rest; sometimes 

 all angular keels are obsolete and the angular portion is only striated. 



Norway — Kara Sea; h. 



4- 



-5 



6—7 



8—9 



max. 9.3 (Varangerfjord) 



25 sps ap. 



2.2 — 



-3 



3.2—3.8 



3.6—5 



4.5 



measured d. 



4- 



-5.2 



5.7—7.2 



7.4—9.4 



8.8 



wh. 



4- 



-4V= 



5 



6—672 



>6 



Norway: The limits of formal variation fall lower here than in the Spitzbergian 

 form. The specimens have therefore a more conical shape and are never depressed. 

 2 — 3 umbilical keels and feeble angular keels or striae are present. — Kara Sea: The 

 individuals here show a resemblance partly to the Spitzbergian and partly to the 

 more elevated Norwegian form. The fossil specimens are of greater dimensions than 

 the living ones. 



Variation of the radula: The number of lamellaj is somewhat varying. Usually 

 there are 9 on each side (Trearenburg Bay; d. 9.5; Newfoundland Bank, d. 7.f; Kil- 

 din Island, d. 7.fi); larger specimens, however, have more lamellae, e. g. 12 (Treuren- 

 burg Bay, d. 12), smaller ones less, 7 8 (Treurenburg Bay, d. 2.7 and d. 4.8). Some- 

 times the lamellae show irregular traces of dentition, but usually they are smooth. 



General Distribution: 



Norway: Vadsö, 10-100 fms (h. 11, G. O. Sars 1878; Schneider 1894); Bog- 

 fjord (Norman 1902); Varangerfjord, 20-380 m (De Guerne 1886). — Murman Coast, 

 White Sea, Nova Zembla and Kara Sea (Herzenstein 1893). — Barent Sea, 275 m (Kni- 

 powitsch 1901'^); 62—168 fms (D'Urban 1880). — Kara Sea, 5—90 fms (h. 11, Leche 

 1878). - Spitzbergen, 9-100 m (Krause 1892; Knipowitsch 190r, 1902, h. 11; Hägg 

 1905). — Franz-Josef Land, 75 fms (Melvill & Standen 1900). — Behring Sea, 65 

 fms (Aurivillius 1887; Krause 1885). — Japan (Jeffreys 1876). — Eastern Canada, to 

 60 fms (Whiteaves 1901). — New England, rare (Gould & Binney 1870). — N. of 

 Hebrides, 170 fms (Jeffreys 1869). Depths to 380 m. Sand, stones, clay, algae. 



Solariella obscura (Couthouy 1839) 

 (inch S. albula Gould, S. bella Verkrüzen and other varieties). 



ri. 5 figs. 15—36; PI. 7 figs. 9—20. 

 Habitat: 



Norway: var. finmarchica (= Machaeroplax obscura G. O. Sars 1878), Hasvig, 

 Finmark, 3 sps, Sars' original, max. h. 4 4; ap. 1.8; d. 5.4; wh. 5, Figs. 35—36. 

 — Var. bella: Lofoten, 200 — 300 fms (M. Sars, det. as Adeorbis subcarinata), 3 sps, 

 max. h. 3.4; ap. l.o; d, 3. it; wh. 4, Fig. 25. — Ulfsfjord (Goes & Malmgren) 1 sh.. 



