278 Panama Shells. tellenida 



Station. — Unknown. 



Habitat. — Bay of Guayaquil, and of Caraccas, Ohiriqui ; 

 Cuming! Hanley. 

 Panama; 0. B. A.I 

 20 odd valves were taken on the beach west of Panama, 



450. nonax navicula. 



Synmiymy. 

 Bmax navicula Hanley in Proc. Zool. Soc. Lond. p. 15. Feb. 1845. 

 Station. — Unknown. 



Habitat. — Gulf of Nicoya ; Cuming 1 Hanley. 



Panama ; B. Jewett I Gould MSS. 



Panama ; C. B. A. 1 

 8 specimens were obtained. 



457. Donax rostratus. Nov. sp. 



Shell elongated, inequilateral, rostrated anteriorly ; ventral 

 edge excurved along the middle, anteriorly rectilinear ; anterior 

 margin very oblique, nearly rectilinear, forming with the ventral 

 edge a rostriform extremity : purple and dingy yellowish brown, 

 more or less in ill defined zones ; interior with the same colors 

 not in zones : posteriorly and near the beaks smooth and shin- 

 ing ; with rather distant very fine radiating striae over the 

 middle of the disc ; striae coarser anteriorly, more distant next 

 behind and more crowded before the umbonial angle ; the latter 

 are slightly rugose : beaks small, prominent : umbones pro- 

 minent; with a very sharp angle separating a concave anterior 

 surface ; within slightly radiately striated ; with the anterior and 

 ventral margins crenulated, more coarsely and deeply at the 

 anterior extremity: with a prominent lateral tooth on each 

 Bide of the cardinal teeth. It somewhat resembles D. cardinatus 

 Hanley. 



Length 1.6 inch ; height 1.15 inch ; breadth .8 inch. 



