Alvania (Cingula) jan-mayeni 5 
på å MA 
Jeffreys (9, p. 553), is evident in the accompanying drawings 
(figs. 1—3). Fig. 3 shows a typical Alvania (Cingula) jan- 
 mayeni Verrill from the coast of New England (the ”Fish 
Hawk“, st. 894) with well-grown spiral ribs. In fig. 2 the 
ribs are more weakly developed, and in fig. 1 they are even 
quite rudimentary. Figs. 1 and 2 are from the ”Michael Sars“ 
st. 70. For comparison I give a figure of the Alvania jan- 
mayeni of the Norwegian Sea from Jan Mayen (”Voeringen*, 
st. 225, 70° 58’ N, 8° 4' W, 357 m, ~ 0,6° C), which clearly 
shows the difference between these two forms. The North 
American form has 3 or 4 more or less well developed spiral 
ribs, while the typical Alvania jan-mayeni has 8 or 10 ”spiral 
furrows“. It seems, however, more correct as to this form 
to use the word ribs, the word used by Leche in his diagnosis 
of Rissoa sibirica (13, p. 38, tab. |, fig. 10). Friele (3, tab. 1, 
fig. 4, 5, tab. 11, figs. 6, 7) as well as Odhner (45, tab. 1, 
figs. 7, 8) give figures showing in the same manner that the 
sculpture consists of ribs. Weinkauff’s drawing (26, tab. 22, 
fig. 13) reproduced by Tryon (20, tab. 65, fig. 28) gives, 
however, the impression that the sculpture is made up of 
furrows. This drawing is, however, not very satisfactory. 
The largest specimens from the ”Michael Sars“, st. 70 
measure: height 4 mm, diameter 25 mm. The same measure- 
ments are given by Verrill. Friele measured the typical Alvania 
jan-mayeni from the Norwegian Sea and found: height 5 mm, 
diameter 2 mm, while Leche gives these measurements as 5 
mm and 3 mm, and Hågg as 5.4 mm and 3.9 mm. 
Alvania jan-mayeni of the Norwegian Sea does not only 
differ from the North American form in sculpture, but also 
in biological respects a difference is noticeable. The typical 
Alvania jan-mayeni was taken by the ”Voeringen* (6, p. 75) 
at Jan Mayen, at Spitsberg and in the western part of the 
Barents Sea, in 128--360 m, bottom-temperature 2.2° to — 
1.4 C. Odhner (15, p. 166) mentions it from the Ice Fiord, 
Spitsberg, 110—406 m, 2.61° to — 1.67° C. At Spitsberg it 
has also been found by Kikenthal (16, p. 94) and the 
Prince of Monaco (2, p. 216), in 188—430 m. Hågg (8, p. 35) 
cites it for the east coast of Greenland in 100 m. The ”Ermak* 
found the species in the eastern part of the Barents Sea, 
