invkkti;i;i;ati-: pal.kontolouy. 41) 



section, from the fad thai all of the shells thai have been identified with it In- 

 European authors arc of the latter type.* 



Compared with Mantell's figure (if we view its upper end as the anterior, 

 and not the hinge-margin, which former seems to be the way it has been 

 generally understood), the shell here under consideration differs in having its 

 beaks less nearly terminal, its anterior margin more prominent, and its poste- 

 rior margin obliquely truncated above, and narrowly rounded below the 

 middle. I know nothing about the convexity of Mantell's type ; but the form 

 here described is more compressed than most of those usually referred to 

 /. Cripsii. With the exception of its obliquely-truncated posterior margin, 

 it seems to agree more nearly with Goklfuss' figures of a shell referred by 

 him to /. Cripsii, but which has been identified by d'Orbigny with a form 

 from the Chalk of France, by him named I. Goldfussii. The identity of the 

 latter with that figured by Goklfuss, however, does not appear to be quite 

 demonstrated by the published figures. 



Although far from being clearly satisfied that our shell really belongs to 

 Mantell's species, I have concluded to place it provisionally as a variety of 

 the same, until some more satisfactory comparisons can he made. 



Locality and position. — Same as last. 



Inocera'mus Cripsii?, var. Barabini, Morton. 

 Plate 13, tigs. 1, a, h, c ; and plate 12, fig. 3. 



Inoceramus Barabini, Morton (1834), Synopsis Org. Kern., 62, pi. 17, rig. 3 (pi. 13, fig. 11 ?). 

 Inoceramus gibbus, Tnoniey (1854), Proceed. Acad. Nat. Sci. Philad., VII, 170. 

 hum ramus cuneatue, Meek and Haydeu (I860), ib., 181. 



For references to original description of /. ' 'rijisii. see synon. of preceding variety. 



Shell transversely ovate, moderately gibbous in the anterior ami umbonal 

 regions, and cuneate posteriorly, very nearly or quite equivalve, rather thin ; 

 anterior margin descending from the beaks at first almost at right angles to 

 the hinge, after which it gradually curves obliquely backward and downward, 

 mi as to pass by a graceful sweep into the base ; posterior side long, com- 



* Mantell's description reads as follows: " Obovate, much depressed, with numerous concentric, 

 transverse ridges; beaks acuminated; posterior side small, depressed; anterior side expanded; hinge 

 oblique .'." 



He figures the shell with its longer diameter ranging vertically ; but from the words "much de- 

 pressed" and ''transverse ridges," it would seem to be transversely elongated, and the hinge on the 

 right side of the figure. Yet the expression "posterior side small, depressed ; anterior side expanded" 

 would scarcely be consistent with this view. He probably described the anterior side as the posterior, 

 and the latter as the anterior, as was the custom with some of the older authors. 



7 ii 



