KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 48,, N:o 1. 53 
W., 27 m, hard mud (E. Nilson '/6€ 1894) 6 sps, with Bryozoa, max. d. 7. — Davis 
Strait, 64” 56' N., 66” 18 W., 15—30 m, sand (E. Nilson +/10 1894) 2 sps, max. d. 7; 
D:o, low water, many sps, max. h. 8; ap. 5; d. 9; wh. 5 '/.. 
Bank of Newfoundland, 46” 5' N., 51”44' W., 56 fms, sand, shells (Ing. & Glad. 
sp rISTLEI spi, h.15:3; ap. 3.35 d. 0; wh. 9. 
Behring Island, low water (Vega Exp. "/, 1879) 2 sps, max. h, 5.7; ap. 4; d. 
8; wh. 4742; shell very solid, Fig. 27. 
Limits of formal variation: 
ORTER — 
OT UN NE SK OO max. 9.8 (Stor Fiord) 
| 
Spitzbergen; h. | 2—3 | 3—4 4—5 | 5—6 
80 sps ap: | 1.5—2.6. |)” 2—3:4 | 2:3—41 3—4.5 | 3.7—4.9 | 3.8—5.5 | 5.2—6.2 | 5.7 
measured | :- .ds;| 219—455 || 4—87-)|. 5-7" | 6—8.6 | 7.3—10 | 8.5—10.8|10.5—12; | Ia 
wh. |3!/2—4 4—A4!/2 | 4!/4—4!/2 425 4!/2—5 z 4!1/2—5 1 BY/4— 5/2 | n 0: fa je 
Greenland ; h. 2—3 3—4 4—5 5—6 6--7 max. 6.5 (Norsouak) max. 8 (Davis Strait 
50 sps ap. | 1.4—2.4 | 2—2.9 | 2.3—3.3 | 2.7—4 | 3.4—4.5 4.3 5 
measured dj | 2:8—-470),3.7—0:7 11 4:8—06:7 | 6:5—7.7 |.T:8—8.2 | 7.9 9 
wh. 3—4 4—4!/2 | 4!/2—5 5 about 5 | 5 5!/4 
West coast of h. 2—3 3—4 AD mr OT 6—7 | max. 6.4 (Finmark) 
Scandinavia; ap. | 1.3—2.2 | 1.9—2.8 | 2.4—3,4 | 2.7—3.8 | 3.2—4.3 | 3.5 
50 sps d. | 2.6—3.2 | 3.5—5.1 | 4:.5—06:8 | 5:7—7.7 | 6:8—8.5 | 7 
measured wh. [3!/1—4"/2 | 4—4!/2 | 5 5 —labout5 | 5 
h. EES | 3—4 | 4—5 max. 4.6 (Berufjord) 
Iceland ; ap. | 1.5—2.3 | 2—3 | 2.5—3.2 | 3.2 
40 sps dö | OR 6 04-56] 14.9—5:8 5.8 
measured wh. |32/,—4 4—4!/2 | 41/2—5 4!/2 | 
The Scandinavian specimens, especially those from the southern districts, such 
as Bohuslän, have a comparatively small diameter (thus are more elevated) than 
specimens from Arctic districts. 
Colour variation: var. fasciata, JEFFREYS 1865, has a spiral band of reddish- 
brown below the suture. 
Variation of the radula: This varies but slightly in the different districts. Form 
and denticulation of the teeth is the same, and the number of uncini only is subject 
to change. Specimens from Bohuslän (full-grown, with a diameter of 3.7) have circa 
50 uncini (Pl. 6. fig. 3); specimens from Norway (Däben; d. 5.1) have 80; those 
from Spitzbergen (d. 9.5) about 80 (fig. 4—5); the specimen from Behring Island (d. 
8) likewise circa 80; specimens from Egedesminde have usually about 80 uncini (2 
sps, h. 5.4; d. 7.2 and h. 5.4; d. 6.6), but one especially high and narrow specimen 
showed only 50. Young animals always have a lesser number of uncini than older 
ones; a specimen from Sukkertoppen (d. 2.2) had only 40, and another from Mossel 
Bay (d. 30) 50. According to Sars, 1878, young specimens have also a smaller num- 
ber of median teeth. One specimen from Norway (Diben) had an aberrant radula 
of the formula 0&.1.(6.1.7).1. 0; the 7th tooth exhibiting some exceptionally 
strong denticles in the outer margin. 
