50 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES 



Fig. 1. 



Fig. 2. 



Inotxramua Bambini, Mortou. 



1. Side view of right valve from Morton's original type-spec- 



imen ; for comparison with our shells. 



2. Anterior profile view of same. 



pressed, and rather regularly rounded ; hinge long and straight, ventral margin 

 forming a broad, semi-ovate curve ; beaks very nearly terminal, or located 

 directly over the anterior margin, rather prominent, but rising little above the 

 hinge, equal, oblique, somewhat incurved, and nearly contiguous. Surface 



ornamented with moderately 

 distinct, more or less regular, 

 concentric undulations. 



Length of a large, rather 

 long specimen, 3.90 inches; 

 height, 2.75 inches ; convex- 

 ity of the two valves, 2 inch- 

 es. Young individuals are 

 proportionally shorter. 



In some of the casts of 



this shell, I.observe a narrow, 



distinct sulcus, passing from 



the back part of the beaks obliquely backward and downward across the 



dorso-lateral region of each valve, as in I. hnpressus, d'Orbigny. This, hovv- 



Fi s- 3 - Fi s- 4 - ever, is not like the broad depression shown 



in Dr. Morton's figure of his /. alveatus, on 

 pi. xvii of his Synopsis, but a sublinear 

 groove (on internal casts) caused by a small 

 ridge only seen on the inside of the inner 

 lamina of the shell. This character, how- 

 ever, is only occasionally present. 



After proposing the name cuneatus for 

 this shell, I had an opportunity to com- 

 pare it with Dr. Morton's types of his 

 Inoceramus Barabini, and find that it 

 agrees so very closely with the first of the two di tie rent forms referred to 

 by him in connection with that name, that I cannot doubt its exact identity. 

 In this connection, however, I should explain that Dr. Morton's fig. 3, pi. 

 17, of his Synopsis, gives a very incorrect idea of the specimen from which 

 it was drawn (as may -be seen from our cut fig. 1, of the same), both 

 with regard to the portions of the specimen preserved, and the outline- 

 restoration of the posterior dorsal region broken away ; which latter 



Another form figured by Mortou under the 

 name /. Barabini; hut not the one he evi- 

 dently regarded as the type. 



Fig. 3. Right side view of Morton's specimen. 



Fig. 4. Profile anterior view of same. 



