292 Panama Shells: macteid^. 



491. Amphidesma ventricosum. Nov. sp. 



Shell suborbicular, subequilateral, ventricose, flexuous ; with 

 the anterior and posterior dorsal margins nearly straight; with 

 the margins otherwise well rounded : dingy white, brownish in 

 ill-defined zones : with unequal striie of growth ; densely 

 covered with radiating microscopic striae : beaks small, approxi- 

 mate : umbones very convex : corselet and lunule not very well 

 defined. 



Length .7 inch ; height .62 inch ; breadth .86 inch. 



Station. — Unknown. 



Habitat. — Panama ; C. B. A. I 

 A single valve only was found, 



492. Crassafella g^ibbosa. 



Synonymy. 



Crassatella gibbosa Sowb. in Proc. Zool. Soc. Lond. p. 56. Mar. 1832. 

 Mull. Syn. Test. Viv. p. 212. May 1836. 



Reeve Conch. Syst. I. pi. 44. f. 2. Sept. 1841. 



Reeve Conch. Icon. pi. 1. f. 1. Jan. 1843. 



lIanleySupp.WoodInd.Te8t.pl. 12. f. 10. 1845? 



Ilanley Descr. Catal. p. 37. 1845 } 



Chenu 111. Conch, pi. 2. f. 6, 12. 



Orb. Voy. Amer. Merid. Moll. p. 5*78. 1846. 



Station. — Sandy mud, 11 fathoms ; Cuming I Sowerby : also 

 Reeve. 



Hahitai. — St. Elena and Xipixapi ; Cuming I Sowerby : also 

 Miiller : also Orbigny : also Reeve. 



Payta; Fontaine 1 Orbigny. 



S. America ; Hanley. 



Punta St. Elena ; Jay. 



Panama ; C. B. A I 

 Only 1 valve was obtained. 



