GASTROPo: 1001 



1 



The true relations of Eotomaria seem to be with Liospir<i. /.I.-/M./. 

 ;in<l Clallirospirn. In Liospira the surface is smoother, the sutures generally much 

 lest distinct, and the hand 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 PI. 

 sulfomarginata Conrad (see accompanying figures) a characteristic species, is 



8. Views of the upper and lower aides of a perfect shell of Bembexia tulcomarginata Conrad sp., 

 natural size, showing longapertural silt and other features distinguishing Bembrxia from Botomaria. The 

 specimen Is from thr Hamilton group of New York, and now In the collection of E. O. Ulrlch. For 

 description and remarks on JScmtaeta tee page* 954 and 966. 



probably a direct descendant of Eotomaria and chiefly distinguished by its long 

 apertural slit Clathrospira has the band directly upon the periphery and a 

 cancellated surface. Euconia, whose relations to Eotomaria 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 Eotomaria 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 //. 

 abrupt ! II rich, 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.dfcipiens I'lrirh. which might easily be mistaken for an Eotomaria, the band is 

 sharply marked an<l 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 Eotomaria. Nothing more was 

 required than to continue the upward movement of the band until its lower 

 boundary coincided with the peripheral edge of the whorl-. 



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 



