256 
AUG. F. FOERSTE 
27 mm. At the uppermost exposed septum, the greatest width 
of the phragmacone is 55 mm., but 10 mm. farther up the width 
of the living chamber is 1 mm. greater. The smallest septum, at 
the base of the specimen, has an estimated width of 25 mm. ; from 
this point the conch widens along the entire length of the phrag- 
macone. The living chamber narrows to 40 mm. at the aperture. 
The general aspect, viewed from the ventral side, is subfusiform. 
The conch is depressed dorso-ventrally. At the top of the phrag- 
macone the ratio of the lateral to the dorso-ventral diameter is 
55 to 50 mm. Toward the lower end of the phragmacone the 
cross-section becomes more nearly circular. 
The lengthwise curvature of the ventral side of the conch is 
convex, with a radius of 105 mm. The lengthwise concave curva- 
ture of most of the dorsal side of the phragmacone has a radius 
of 90 mm., until within a short distance of the base of the living 
chamber. At this upper level the general aspect of the shell is 
tumid or swollen, the dorsal outline changing from concave to 
slightly convex. In a general way, this convexity of outline ex- 
tends from the base of the third camera beneath the living 
chamber to mid-height of the latter, above which the dorsal out- 
line is slightly concave again. The contraction of the living 
chamber, both laterally and dorso-ventrally, is quite regular as 
far as the aperture, with a very faint decrease in the rate of 
contraction within 5 mm. of the margin of this aperture, in the 
type, but not in other specimens of this species. 
Septa with a concavity of 10 mm. occur at a point where the 
width of the conch, not the type, is 54 mm. The sutures of the 
septa appear to be nearly straight on the dorsal and lateral sides, 
but incline slightly downward toward the ventral side. If there 
is a tendency toward a slightly concave curvature of the sutures 
on the ventral side, this is not known definitely, although sus- 
pected from the inclination of the three septa seen on the ventral 
side of the type, where part of the shell has spalled off. In 
analogy with the species originally described as Cyrtoceras lat- 
erale, the siphuncle is located on the ventral side of the conch, 
about 3 mm. distant from the ventral wall. 
The surface of the shell is crossed by low, broad, transverse 
bands or lines of elevation of which 12 occur in a length of 
20 mm. These bands are deflected downward on the ventral side 
of the more inflated part of the conch for a distance of 3 mm. 
