114 BULLETIN OF THE 



Avicula atlantica Lamarck. 



The specimens are all small, very thin, briglit colored, and mostly of a 

 yellowish tint. They seem abundant. The normal form exteuds from Cape 

 Hatteras to Rio de Janeiro. 



Perna obliqua Lamahck 



Except in their small size, these are hardly different from the common form 

 of the species, which has a wide distribution in Florida and the Antilles. 



Tellina mera (Say) Hanley 



This is a small white shell, which seems common in the lagoon, and is 

 slightly thinner and smaller than the outside examples of the species. It ex- 

 tends from the Florida Keys to South America. 



Cyrena colorata Prime. 



Though having well established characters, this species is closely related to 

 C. floridana Conrad, from which it may perhaps be descended. It is known 

 only from the lagoons of South Florida and the Bahamas, It is extremely 

 thin, and varies from white to dark brown, bright pink, purple, bright orange 

 or lemon-yellow, etc., generally diffused, or distributed in concentric zones. 



Venus (Anomalocardia) leptalea n. sp 



Figure 5. 



This is another form strictly confined to the lagoons. It is closely related to 

 V (A.) rostrata Sby., which is its open-sea representative, and which was fii-st 

 described by Conrad from Florida imder the name of Venus cuneimeris (Proc. 

 Acad. Phila., III. 24, Plate I. Fig. 13, 1845). From the latter V. leptalea 

 differs by its smaller size (1.3-16 mm.), papery thinness, less impressed dorsal 

 areas, its concentric ribs reyjresented by elevated lamella?, instead of rounded 

 wavelets, and its color by zigzag lines, rather than radiating bands. The vari- 

 ations in outline are about the same in both ; there are no traces in V. leptalea 

 of radiating sculpture, the dorsal areas are usually dark, even if the rest of the 

 valve is pale , the hinge is very feeble and the pallial sinus obsolete. The 

 group is also known as Cryptogramma Morch. 



Haminea antillarum Orbigny. 

 A single depauperate specimen has been received. Common in the Antilles. 



