292 Panama Shells. 



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 striae 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 .36 inch. 



Station. Unknown. 



Habitat. Panama ; C. B. A. ! 

 A single valve only was found. 



492. Crassatella gibbosa. 



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. 



- Hanley Supp. Wood Ind. Test. pi. 1 2. f. 1 6. 1845? 



- Hanley Descr. Catal. p. 37. 1845 ? 



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



- Orb. Voy. Amer. Merid. Moll. p. 578. 1846. 



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

 Reeve. 



Habitat. St. Elena and Xipixapi ; Cuming ! Sowerby : also 

 Muller : also Orbigny : also Reeve. 



Payta; Fontaine! Orbigny. 



S. America ; Hanley. 



Punta St. Elena ; Jay. 



Panama ; C. B. A ! 

 Only 1 valve was obtained. 



