TELLINID^. 113 



by a thickening of the margins ; ligament external, apparently 

 on the shorter side, inner edge of shell occasionally crenated. 

 Lea described several somewhat different species under this 

 genus. Conrad referred the orbicular forms to Mj-sia and Sphse- 

 rella, and they certainly belong to the Lucinidae, reserving the 

 name Egeria for such forms as Eg. sublrigona (cxii, 90) and 

 ovalis of Lea. These shells externally very much resemble the 

 subgenus Moera of Tellina, but as the latter never have the inner 

 margin crenated, it is probable that the present classification of 

 the group is the more correct one. Conrad, in his Check List of 

 Eocene North American Fossils (1866), refers seven species to 

 the gronp. Deshayes and others describe similar tertiary forms. 

 ONCOPHORA, Rzehak, 1882. Founded upon 0. socialis, Rzeh., 

 a tertiary fossil, supposed to have inhabited brackish water. 

 (Verh. K. K. Geol. Reichs., No. 3, 41, 1882.) 



Iphigenia, Schumacher, 181t. 



Syn. — Capsa, Lam., 1818. Donacina, Fer. 



Distr. — 5 sp. West Indies, Brazil, West Africa, Pacific, Cen. 

 America. /. Brasilien^is, Lam. (cxii, 88). Inhabits estuaries. 

 /. ventricosa, Desh., has eroded beaks. . 



Shell transverse, subequilateral, gibbous, covered with a thin 

 olivaceous epidermis ; hinge-teeth 2-2, one bifid, the other minute; 

 laterals remote, obsolete in the left valve ; margins smooth. 



FiscHERiA, Bernardi, 1859. 



Etym. — Dedicated to Dr. Paul Fischer, one of the able editors 

 of the Journal de Conchjdiologie. 



Distr. — 2 sp. F. Delesserti, Bern, (cxii, 89). Africa. 



Shell transverse, equivalve, subequilateral, close, rather thick, 

 with epidermis ; right valve with a median, longitudinally chan- 

 neled cardinal tooth, with additional rudimentarj^ cai'dinals ; 

 left valve with a median pit (to receive the cardinal of the other 

 valve), and two slightly oblique, lateral cardinals; right valve 

 with extremely thin, compressed lateral teeth, none in the left 

 valve ; muscular impressions distinct, pallial sinus large and 

 deep ; ligament short, rather elevated. 



Galatea, Bruguiere, 1192. 



Syn. — Egeria, Roissy, 1805. Potamophila, Sowerby, 1822. 

 Megadesma, Bowdich, 1828. Galateola, Fleming, 1828. 



Distr. — 16 sp. Nile, and rivers of West Africa. G. radiata, 

 Lam. (cxii, 91). G. reclusa, Born (cxii, 92). 



Shell very thick, trigonal, wedge-shaped ; epidermis smooth, 

 olive ; umbones eroded ; hinge thick, teeth 1-2, laterals indistinct; 

 ligament external, prominent ; pallial sinus distinct. 



Animal with the mantle open in front ; siphons moderate, with 

 6-8 lines of cilia, orifices fringed ; foot large, compressed ; palpi 



