MUSEUM OF COMPARATIVE ZOOLOGY. 209 
and prominent transverse nodules, and on the body whorl conspicuous widely 
separated spiral threads. Spire about half the length of the shell, acutely coni- 
cal in outline, ornamented with prominent nodules just above the sutures, and 
with a shining, pale yellowish brown tip. Aperture narrow, oblique. Poste- 
rior sinus deep, as broad as the subsutural band. Outer lip thin, reaching 
far forward, curving in anteriorly, forming a short, narrow canal, and joining 
the columella in a regular curve without any notch. Columella very strongly 
curved with a thin, ill-defined layer of enamel. Suture defined by a fine 
rounded thread. Subsutural band, crossed only by the very conspicuous, 
strongly curved lines of growth intersected by indistinct microscopic striz, 
reaches to the periphery of the whorls, where prominent, nearly straight, 
oblong, angular, transverse nodules, fifteen on the body whorl, rise very ab- 
ruptly and terminate just above the suture, and are separated by spaces about 
equal to their own width. On the body whorl, below the nodules, there are 
twelve conspicuous, raised, rounded, widely separated threads. The space be- 
tween them measures about 0.5 mm.; on the canal it decreases slightly, so that 
the last four or five threads are a little nearer together. The lines of growth 
are clearly defined and, under the microscope, are everywhere intersected by 
indistinct strie. Minute microscopic granules are scattered over the entire 
surface, scarcely discernible on the nuclear whorls. Apical whorl small, 
smooth, slightly raised above the next whorl, which, with the succeeding turn, 
forms the nucleus. These are ornamented with a fine, distinct peripheral keel, 
which under the microscope is found to be divided into minute beads. There 
is no operculum. The animal is drawn so far into the shell as to render the 
study of it impossible. 
Length, 11 mm.; breadth, 5 mm.; length of aperture, 5.5 mm. 
This is a very beautiful species, and quite distinct from any known form. 
Mangilia leuca, sp. nov. 
Plate I. Fig. 2. 
One living specimen, Station 329, off Cape Lookout, N. C., in 603 fathoms. 
Shell rather large for the genus, regularly fusiform, thin, translucent, bluish 
white, with a roughened surface of waxy lustre, and a shining tip of a delicate 
yellow tint. Spire about half the length of the shell, of seven decidedly shoul- 
dered whorls, besides the nucleus. Aperture long and narrow. Posterior sinus 
large and nearly round, commencing at the suture and reaching to the shoul- 
der, cutting into the top of the varix formed by the thickening of the last 
transverse rib, thus showing a thickened border with the upper edge rounded 
but not raised above the surface of the shell, extending farther back than the 
inner edge and curving strongly with the lines of growth, nearly meeting in 
front ; from this the thin outer lip reaches far forward over the aperture, leav- 
ing a very narrow opening. Near the anterior end it is pinched in slightly, 
then bends abruptly backward as though cut off obliquely, revealing the entire 
