116 TRANSACTIONS OF THE WAGNER FREE 



LAMELLIBRANCHIATA. 



Venus penita, Conrad. 



Am. Journ. Science, second ser., ii, p. 399. 

 f Venus Floridana, Conr., id., ii, p. 400. 



Shell cuneiform, evenly rounded anteriorly, produced posteriorly ; 

 base sinuous ; umbones prominent, overlooking a broadly cordiform 

 lunule; the posterior slope sharply angulated, the angulation preceded 

 by a gentle undulating fold ; ligamental margin very oblique, and straight 

 from umbo to extremity ; cardinal teeth robust ; external surface covered 

 with fine concentric lines, the series interrupted at irregular intervals; 

 base crenulated. 



Length of largest specimens, 1.3 inch ; height, nearly one inch. 



The shell is not produced posteriorly to the extent that is represented 

 in Conrad's figure, which is taken from a cast ; nor is the anterior portion 

 prolonged much beyond the beaks, so that despite its peculiar cunei- 

 form outline the shell appears high. I have little doubt that Conrad's 

 V. Floridana is the young of this species, which is closely related to the 

 recent V. inacrodon of Deshayes, from the coast of Central America. 

 The latter form is distinguished by its much coarser ribs, and the inter- 

 stitial semi-line that appears on the posterior angulation. 



Venus magnifica, Sowerby.. 



Thesaurus Conchyliorum, ii, p. 704, pi. 153, fig. 5 ; Gabb, " Santo Domingo," Trans. 

 Am. Philos. Soc., xv, p. 249. 



A single valve, which is undistinguishable from the Dominican fossil 

 (Miocene) and the recent species of the Philippine seas ; it differs from 

 V. puerpera in having a straight hinge-line. In the collection of the 

 Academy of Natural Sciences of this city there is an undetermined 

 species of Venus from Egmont Key, Florida, which is very closely re- 

 lated to our fossil. It differs in the want of regularity of the concentric 

 raised lines, and in its broadly cordiform lunule. 



? Cytherea staminea, Conrad. 



Foss. Med. Tert. U. S., pi. 21, fig. i. 



Two valves, which differ in but insignificant details from the Miocene 

 fossil of the Atlantic slope. 



T Cytherea Sayana, Conrad. 



Foss. Med. Tert. U. S., p. 13. 



A single valve, which has much the aspect of this species, but is a 

 somewhat longer shell and less convex proportionately. It may possibly 

 represent a distinct form. 



Cytherea nuciformis, nov. sp. Fig. 61. 



Shell erect, sub-trigonal, moderately convex ; base evenly rounded, 

 posterior slope rapidly declining ; beaks elevated ; surface covered with 



