DALL: MOLLUSCA AND BRACHIOPODA. 303 
ated, twisted, almost pervious ; aperture narrow ; outer lip very thin, sharp, con- 
cave near the shoulder, produced in front, modified by the sculpture, but not 
lirate. Height of (eroded) shell, 305 of last whorl, 21; diam. 9 mm. , 
U. S. S. “Albatross,” stations 3300, 3374, 3399, and 3415, in 1970 to 1879 
fathoms, Gulf of Panama to Acapulco, sandy or oozy bottom, temperatures 36*.0 
to 36?.4 F. U.S. N. Mus. 123,006. 
This elegant little shell recalls Boreotrophon in its sculpture. The spirals in 
some of the specimens are narrower and more numerous than in the type, and 
in the young the ribs are less sharp and the color more ashy. 
TROSCHELIA Morcn. 
Troschelia Mirch, Journ. de Conchyl., 1876, 24, p. 870; type, Fusus berniciensis 
King. Not Troschelia Duncan, Echinidae, 1888. 
Boreofusus G. O. Sars, Moll. Reg. Arct, Norv., 1878, p. 278; type, B. berniciensis 
King. 
Shell elongate, fusiform, with a produced recurved canal, a short, rounded- 
triangular operculum with apical nucleus, slightly sinistrally curved; the radular 
formula dy + 4+ yy, the cusp of the rhachidian plate well developed, nearly as 
long as the base; animal having the eyes developed. 
Thalassoplanes Dati, subg. nov. 
Shell short, the canal very short, the operculum straight, elongate, wedge- 
Shaped, the extreme apex slightly turned to the right; radula (of the type) with 
the formula $ + $ + 4, the rhachidian plate with the cusp obsolete ; animal blind, 
male with a small, subeylindrie verge, without appendices. Type 7. mörehii Dall. 
Troschelia (Thalassoplanes) mörchii Datz, n. sp. 
Shell short, stout, with about five whorls, of which two are nuclear, polished, 
depressed, smooth ; subsequent whorls uniformly sculptured with (between the 
Sutures seven, on the last whorl nine or ten) narrow, similar, flat-topped, elevated 
ridges, with much wider, equal interspaces, and on the canal seven additional 
Spiral threads ; this sculpture is crossed by numerous (three or four to a milli- 
meter) equal and equally spaced, flexuous, smaller elevated axial threads, which 
override the ridges and divide the channels into reetangular spaces; the whole is 
Covered by a fibrous, thin, olivaceous periostracum ; suture distinet, not chan- 
nelled; whorls turgid and evenly rounded; aperture nearly equal to the spire, 
Outer lip thin, sharp (in the adult reflected ? ), body and inner lip slightly 
erased, white; pillar short, twisted, its anterior edge thiekened and flaring 
anteriorly, obliquely attenuated ; axis pervious ; canal almost obsolete, with no 
Siphonal fasciole; operculum thin, brownish, pinna-shaped, the area of attachment 
