98 JAMES A. GRIEG. [SEC. ARCT, EXP. FRAM 
Trichotropis bicarinata, Broperie & SoweERBY. 
(Figs. 4—8). 
Locality: . 
July 22. 1900. The winter harbour, Havnefjord, about 60 m. Small stones. A 
rather damaged specimen measuring: total height 30 mm., largest 
diameter 24 mm., length of aperture 17 mm., breadth of aperture 
13 mm. 
The shell (fig. 4, a—b) is quite thin, translucent, white and covered 
by a skin-like wrinkled dirty yellowish-white epidermis. Sculpture con- 
sists of close, fine, oblique, longitudinal lines. Fine spiral striae are 
also visible under the microscope. Number of whorls 6, of which the 
last is decidedly ventricose. The apical whorls are white, smooth and 
convex. The last whorl is furnished with two sharp spinal carinae, 
which are densely covered with large well-develoved setae. The penul- 
timate whorl has a setiferous spiral carina. The two remaining whorls 
seem also to be furnished with spiral carinae, but it was impossible to 
examine them closely owing to their being covered by a sponge. Aper- 
ture is sub-circular and somewhat more than half the length of the shell. 
Umbilicus deep and partly covered by the columella, which is excurved 
and has a slight indication of a canal at its base. On the outer side 
the umbilicus is bounded by a sharp carinae, which like the spiral 
carinae is thickly covered with setae. Operculum (fig. 4c) is triangular 
(6 X 6.5 mm.) and of the same form and structure as in trichotropis 
hjorti, Friete. Radula also resembles that of this species. 
The specimen belongs apparently to the variety trichotropis tenuis 
from Grinnell Land described by Smiru: though Smitus specimen, which 
was of about the same size (33 mm.), appears to differ from it in having 
a more slender and more tapering spire, and further does not seem to 
have such well-developed setiferous filaments on the spiral carinae or 
on the umbilical carina. This latter carina moreover in the Fram speci- 
men is placed in a position more resembling that of trichotropis bicari- 
nata Brop. & Sow. (Cf. Tryon: Manual of Conchology, vol. 9, tab. 7, 
fig. 42). The whole appearance of the specimen too reminds one not 
only of trichotropis tenuis but also of trichotropis bicarinata, and 
I am accordingly most inclined to accept the view of Jerrreys that 
trichotropis tenuis is a monstrous variety of the last-named. 
We must also include trichotropis hjorti, Frmiz as a variety of 
trichotropis tenuis, a fact I have already alluded to in the report on 
the “Belgica” expedition of 1905. This form was first discovered in 
1900 by the Norse Fishery Steamer “Michael Sars” in the cold area 
