l'"\<J. 22H 



Synopsis Frf:sh-Wati?,r Moi,i,usca 

 Genus MUSCULIUM Link 1807. 



87 



Shell thin, suborbicular or oblong, smooth, shining, 

 stri^ very fine and delicate ; beaks calyculate ; cardinal 

 teeth minute, often obsolete. 



Type : Tellina lacustris Miill. 



Example: M. jayanum (Pme.), fig. 228. Animal, M. 

 tnincatum (Lins.). fig. 229. 



Fig. 229 



M. — Mouth. 



Lp. — Labial palps. 



Es. — Oesophagus. 



Lv. — Liver. 



Sto. — Stomach. 



Int. — Intestine. 



R. — Rectum. 



A. — Anus. 



CbG. — Cerebral ganglion. 



PsG. — Parieto-splanchnic ganglion. 



PG. — Pedal ganglion. 



Sta. — Statocyst. 



V. — 'Ventricle. 



Au. — Auricle. 



PI. — Pericardium. 



KO. — Kidney opening. 



T. — Sperm follicles. 



O. — Egg follicles. 



GD. — Genital opening. 



AA. — Ant. adductor muscle. 



PA. — Post, adductor muscle. 



Ft.— Foot. 



ClCh. — Cloacal chamber. 



ExS. — Excurrent siphon. 



InS. — Incurrent siphon. 



G.— Gill. 



Man.— Mantle. 



Shi.— Shell. 



Kd. — Kidney. 



Fig. 230 



Genus EUPERA Bourguignat, 1854. 



Shell subrhomboidal. Moderately inflated, thin, with 

 the posterior side longer ; cardinal teeth feeble, one only, in 

 each valve. Animal as in Sphcerium. 



Type : Pisidiiim moquinianum Bgt. 

 Example: E. singleyi (Pils.), fig. 230. 



