KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 50. N:0 5. 39 



The radula thus shows the same conditions as the shell, being somewhat reduced 

 in size iii soiithern districts and deep water. 



In the structure the radula is not subject to great variation. The median tooth 

 is always aboiit twice as broad as it is long, never much larger. Its side-cusps are com- 

 paratively small, not exceeding half the length of the central cusp, sometimes bifid 

 (e. g, Ritenbenk; sh. h. 9.5) or replaced by irregular denticulations (e. g. Väderöarna, sh. 

 h. 13.4, Laholmsbukten, sh. h. 17. s). The last-named character appears generally in older 

 specimens with worn teeth (e. g. Vega St. 1042, sh. h. 32). The laterals have from one 

 to three outer and from one to two inner small cusps, or else are smooth (e. g. Vega St. 

 1042). In the inner uncini the outer cusp is of the same size or shorter than the inner 

 one, which is, hovt^ever, usually slender. The inequality in size is especially striking in 

 the large specimens from Behring Sea. In smaller specimens (Vega St. 1068, sh. h. 5.5) 

 the radula is in all respects typical, 



Gener.al Distribution: 



Norway: the whole coast to Vadsö, O — 250 fms (h. 22, G. O. Särs 1878); Varanger- 

 fjord, 23—325 m (De Guerne 1886); East Finmark (Norman 1902); Northern Norway 

 (Verkriizen 1875; Sparre Schneider 1881, 1886, 1891, 1894; Aurivilhus 1886; Krause 

 1887; Bidenkap 1897); Trondhjem (M' Andrew 1856); West coast, 90— 217 fms (Metzger 

 1875); Lindesnöes, 343 m (Dautzenberg & Fischer 1912); Christianiafjord 40 — 60 fms 

 (Jeffreys 1870). — Väderöarna, 80 fms (Malm 1855). — N. of Skagen, Kattegatt to H ven, 

 15—70 fms, clay (Mörch 1871; Petersen 1888; Lönnberg 1908). — Dogger Bank; Scar- 

 borough (Hargreaves 1910). — Holland and Belgium (Maitland 1897). — Northumber- 

 land; Durham; Yorkshire, 40—60 fms; Shetland (Jeffreys 1867); N. of Hebrides, 189 

 and 650 fms (Jeffreys 1869); N. of Scotland, 540 fms (Jeffreys 1885); betwene Shetland, 

 Scotland and Norway, 98—361 m (Simpson 1910); W. of Ireland, 173—458 fms (Jeff- 

 reys 1885; Nichols 1900). — North Atlantic, 20—658 fms (Friele & Grieg 1901). — 

 Murman coast, White Sea, N. Zembla, Kära Sea, Sea off Siberia (Herzenstein 1893; 

 Leche 1878; Aurivilhus 1887; cfr above). — Barent Sea, 62—160 fms (D'Urban 1880); 

 Kolguev Island (h. 38; Middendorff 1849); W. and N. of N. Zembla, 111—375 m; S. E. 

 of Franz-Joseph Land, 323 m (Knipowitsch 1901'"^). — Kära Sea (Collin 1887). — Behring 

 Sea to Aleiitians (Dall 1875; Crosse 1877; Krause 1885; Aurivilhus 1887). — Sea of 

 Ochotsk, Great Schantar Island (Middendorff 1849, 1851; Schrenk 1867; Dunker 1882). 



— Japan, 3 fms (Jeffreys 1870), — Pugefs Sound, Vancouver (Carpenter 1864). — 

 E. Spitzbergen (Krause 1892); Stor Fiord, 9—117 m (h. 37.0, Knipowitsch 1901", 

 1902); 71° 21' N. 17° 32' E., 278 m to 81° 1' N. 19° 28' E., 180 m (Knipowitsch 1901"). 



— W. Spitzbergen (Mörch 1869*^; Friele 1879; Friele & Grieg 1901; Dautzenberg & 

 Fischer 1912). — Jan Mayen, 15— 30 m (Becher 1886), 70— 300fms (Friele 1878; 1902). — 

 Iceland (Mörch 1869; Verkriizen 1872). — Danmark Strait, 550 m (Friele 1902). — 

 E. Greenland (Hägg 1905, cfr above). — W. Greenland (Posselt & Jensen 1899, cfr above). 

 Jones Sound, 14—20 m (max. h. 26, Grieg 1909). —Wellington Channel (Reeve 1855). — 

 Hudson Bay to E. Canada, 3 — 60 fms (Whiteaves 1901). — Grand Månan to Cape Cod 



