536 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiv. 
The very peculiar sculpture recalls that of some species of Cancel- 
lariidse of the genus Trigono^toma. In the young the revolving threads 
are more prominent than in the older specimens. U.S.N.M., 98451. 
? TROPHON UNICARINATUS Philippi. 
Eusii^ unicarinatusV's.wAwx, Malak. Blatt., XV, Dec, 1868, p. 223. 
Trophon unicarinatus Teyon, Man. Conch., II, 1880, p. 151. 
Magellan Strait, Acton, Jide Philippi; dredged by the U. S. Fish 
Commission steamer Albatross in the strait, at station 2777, in 20 
fathoms, gravel, U.S.N.M., 96193. 
The little shell described by Philippi under the name of Fusus has 
much the aspect of a miniature ('hri/Kodomiix of the desjx'ctu.s type. 
If so it is the only representative of that group in the Antarctic. It is 
more likel}^, in spite of the resemblance, that it is related to the Tro- 
plion^ so abundant in these seas. Unfortunately all the specimens 
dredged were destitute of the soft parts, so that the anatomical fea- 
tures and operculum remain unknown. 
The nucleus is large for the size of the shell, smooth, inflated, and so 
loosely twisted that it at lirst suggests a sinistral l)eginning, which is 
not contirmed by a closer examination. The whorls are flat above, 
with a strong, l)lunt peripheral carina and a second less prominent 
keel, just ])elow the periphery, on which the suture is laid. The sur- 
face is axially faintly striated by the incremental lines. The l)ase is 
moderately rounded and passes into a slightly recurved canal as in 
Chrysodomus. The bod}^ of the shell is of the pale brown, with a slight 
tinge of purple, characteristic of the Arctic Chrysodom!, but the pillar 
is white and so is the canal, and the keels are lighter than the bod}^ 
color of the shell. The outer lip is simple and hardly thickened and 
the throat smooth. The largest specimen obtained ])y the Fish Com- 
mission was 8.5 mm. in length and 5 mm. in maximum width. The 
longest diameter of the aperture was a little less than 5 mm. ; there 
were two nuclear and thi'ce subsequent whorls. 
Altogether it is a remarkable little shell, which a comparison with 
the young of several of the larger prosobranchs of the region indi- 
cates to be a well-deflned and distinct species, worthy of more thorough 
study than my material makes practicable. 
GENUS BOREOTROPHON (Fischer) 1884.' 
In briefly reviewing the group it may be useful to enumerate the 
boreal species by geographical regions, namely, that of North Europe, 
including the northeast Atlantic, Iceland, and Greenland, which 
belongs more to Europe than America, faunall}'; of the northeast 
coast of North America, including the cold deep waters adjacent 
which carry boreal species far southward of their natural habitat if 
^If Bolten's undefined names are to be accepted this genus, by elimination, must 
take the name of Neptunea. 
