THE NATURAL HISTORY SURVEY. 4 221 
very rapidly enlarging, not much expanded, the last whorl over 
twice the size of the others combined; spire very short, acute- 
conic; sutures very heavily impressed; aperture long-ovate, 
Narrow, straight, wider below than above the center, where it 
rapidly narrows to an acute point; the aperture occupies from 
two-thirds to three-fourths the length of the entire shell and is 
somewhat patulous; when the shell is viewed from below, all 
the volutions may be seen within the aperture; peristome thin, 
simple, terminations widely separated; columella simple; a 
view from the side shows the shell to be more or less cone- 
shaped. 
Length, 19.50; width, 9.00; aperture length, 14.00; wide, 7.00 mill. (6891.) 
 guoap oe 53a amo 0 Pace ‘ 12005 G50. ** - .(9699)) 
af PWS sate CBO? 6h 8.50;. “' 5,00 “ (10124.) 
Animal: Generally whitish or amber colored, the upper 
part of the body covered with minute brownish or blackish 
dots arranged in clusters; there is a black line on the upper 
part, which extends from the ends of the eye-peduncles, along 
the sides of the neck to the shell; eye-peduncles short, thick, 
not much tapering, the eyes situated on bulb-shaped swellings 
at the tips; tentacles very short, conical; foot longand narrow, 
truncate before and pointed behind, 9.50 mill. long, and 2.00 
mill. wide; the head is distinct and separated from the body by 
a neck; respiratory orifice on the right side of the shell near 
the peristome, about a fourth of the distance between the an- 
terior and posterior borders of the latter. Heart situated to 
the left of the aperture, midway between upper and lower mar- 
gins; pulsations somewhat irregular, one hundred and fifty to 
one hundred and fifty-five per minute. 
Faw: “Arched, ends blunt; cutting edge with a central 
projection and three smaller swellings on each side; anterior 
surface smooth. The usual superior appendage is present. 
A specimen examined by Morse had the anterior surface cut 
up into several vertical furrows which modified the lower mar- 
gin. Binney found a jaw with smooth anterior surface and 
strong median projection (Fig. 56, J). 
Radula formula: +8+%+4+4+%+ +48 (60—1—60); cen- 
tral tooth longer than wide, the lower part of the base of 
attachment produced at the outer corners, reflected portion 
tricuspid, the central cusp very long but not reaching the 
lower margin of the base of attachment, and the side cusps 
small; lateral teeth almost as wide as long, similar to central, 
