646 SYSTEMATIC PALEONTOLOGY 



anterior cardinal tooth of the left valve trigonal, and deeply emarginato 

 below ; posterior very much compressed, oblique, and somewhat elongated ; 

 cardinal teeth of right valve diverging, with a triangular pit between for 

 the reception of the larger triangular tooth of the other valve; anterior 

 one small, oblique, and connected at its upper end with the posterior 

 extremity of the anterior lateral ; posterior larger, oblique, longitudinally 

 furrowed, 1 and perhaps emarginated below, while just behind and above 

 it there is a narrow oblique slit, or pit, for the reception of the thin 

 anterior cardinal of the other valve ; lateral teeth elongated parallel to the 

 cardinal margins ; the anterior one of the right valve, and the posterior of 

 the left, apparently continued so as to connect with the upper ends of the 

 cardinal teeth ; ligament external ; pallial line simple. 



" The typical species of this genus has the general external appearance 

 of a Crassatella, from which genus, however, it is clearly removed by its 

 hinge characters, though evidently belonging to the same family. Its 

 muscular impressions are faintly defined, as is also the case with the 

 pallial line, which latter, however, can be followed so far back as to leave 

 little or no doubt that it is really simple. The larger trigonal cardinal 

 tooth of the left valve is probably sometimes so deeply emarginate as to 

 give it an A-shape." Meek, 1876. 2 



Meek's belief in the identity of the two genera has been sustained by 

 later paleontologists. There is no record of the group from other than 

 Cretaceous strata. 



CRASSATELLINA CAROLINENSIS (Conrad) Meek 

 Etea carolinensis Conrad, 1875, Kerr's Geol. of North Carolina, App., p. 6, 



pi. i, fig. 14. 

 Crassatellina carolinensis Meek, 1876, Kept. U. S. Geol. Survey, Territories, 



vol. ix, pp. 119, 120. 



Etea carolinensis Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 14. 

 Etea carolinensis Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, 



p. 541, pi. lix, figs. 4-6. 



Description. " Shell suboval, short, equilateral, compressed, with dis- 

 tinct lines of growth ; posterior end truncated, nearly direct." Conrad, 

 1875. 



1 The furrow of this tooth is too strongly defined in fig. 3d, of plate 2. 

 3 Kept. U. S. Geol. Survey, Territories, vol. ix, pp. 119, 120. 



