GASTROPODA. 1001 
Eotomaria.] 
The true relations of Hotomaria seem to be with Liospira, Huconia, Bembexia 
and Clathrospira. In Liospira the surface is smoother, the sutures generally much | 
less distinct, and the band less sharply defined, convex instead of concave, and turned 
partly over the peripheral edge instead of being placed entirely upon the upper 
side. Bembexia, which is mostly a Devonian genus, and of which we consider Pl. 
sulcomarginata Conrad (see accompanying figures) a characteristic species, is 
Fig. 6.—Views of the upper and lower sides of a perfect shell of Bembegia sulcomarginata Conrad sp., 
natural size, showing long apertural slit and other features distinguishing Bembexia from Hotomaria. The 
specimen is from the Hamilton group of New York, and now in the collection of H. O. Ulrich. For 
description and remarks on Bembexia see pages 954 and 955. 
probably a direct descendant of Hotomaria and chiefly distinguished by its long 
apertural slit. Clathrospira has the band directly upon the periphery and a 
cancellated surface. Huconia, whose relations to Hotomaria perhaps are more 
apparent than real, has a more strictly conical form, more numerous whorls and a 
flattened base, while the anterior outline of the under lip is straight excepting in its 
extreme outer part where it turns slightly backward before it reaches the lower edge 
of the band. 
We believe Hotomaria was derived from Liospira. Although the actual 
connecting links are unknown, we can, after a comparison of known species, readily 
imagine the modifications required to produce the main distinguishing feature of 
Eotomaria, viz.: a concave band lying entirely upon the sloping upper side of the 
volutions instead of a convex band lying upon the peripheral edge, and partly visible 
in a view of the base. In the most typical species of Liospira no part of the band 
can be described as concave and both margins are very distinctly defined. In L. 
abrupta Ulrich, however, the upper border of the band is better defined and an 
appreciable concavity lies between it and the extreme periphery of the whorl. In 
L. decipiens Ulrich, which might easily be mistaken for an Hotomaria, the band is 
sharply marked and its upper part decidedly concave, while only a small portion ot 
the band turns over the peripheral edge. After reaching this stage but a small step 
remains to bring us quite within the limits of Hotomaria. Nothing more was 
required than to continue the upward movement of the band until its lower 
boundary coincided with the peripheral edge of the whorls. 
To give a just idea of this new generic group we have illustrated all of the 
six species which we are reasonably satisfied belong here. All belong to the 
