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 ÄR ter portion is only striated. 
| [ | 
| 6—7 | 8—9 | max. 9.3 (Varangerfjord) 
| NS Sea; h. 4—5 | 
25 sps ap. | 2.2—38 | 3.2—3.8 | 3.6—5 | 4.5 
measured d. 4—5.2 är D:0 1.2 | i1:29:4 | 8.8 
| wh. | 4—4!132|. 5& | 6—06!/2] >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 strie 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 lamelle is somewhat varying. Usually 
there are 9 on each side (Treurenburg Bay; d. 9.5; Newfoundland Bank, d. 7.9; Kil- 
din Island, d. 7.6); larger specimens, however, have more lamelle, e. g. 12 (Treuren- 
burg Bay, d. 12), smaller ones less, 7—8 (Treurenburg Bay, d. 2.7 and d. 4.38). Some- 
times the lamelle 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 1901", 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, alga, 
Solariella obscura (CoutTHouYyY 1839) 
(inel. 5. albula Gourp, 9. bella VERKRUZEN and other varieties). 
Pl. 5 figs. 15—36; Pl: 7 figs. 9=20. 
Habitat: 
Norway: var. finmarchica (= Macheroplax 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 subcearinata), 3 sps, 
max. h. 3.4; ap. 1.9; d. 3.9; wh, 4, Fig. 25. — Ulfsfjord (Coös & Malmgren) 1 sh., 
