SPH^ERIUM. 53 



c. SHELL ALWAYS SMALL, RHOMBOIDAL, BEAKS CALYCULATE. 



31. Spliaerium bahiense, SPIX. Animal not observed. 



Shell very small, rounded-oval, inflated, inequi 

 lateral ; anterior margin narrow, curved; posterior Fig- 

 margin broad, subtruncate ; inferior margin curved ; 



beaks inclined towards the anterior, large, prominent, 

 calyculate ; valves slight, interior dark yellow, irregu 

 larly mottled with dark reddish spots ; lines of growth 

 very fine ; epidermis yellowish-brown, with irregular 

 spots of dark purple ; hinge-margin very narrow, g bahiense. 



nearly straight ; cardinal teeth small ; lateral teeth 

 comparatively strong, the posterior one much the longer. 



Long. 0.15; Lat. 0.12; Diam. 0.09 inches. 



Hab. South America, at Bahia in Brazil. (Cabinets of Jay, Prime and 

 others.) 



Cyclas bakiensis, SPIX, Test. Braz. 1827, 32, pi. xxv, f. 5, 6. 

 Cyclas maculata, ANTOX (non MORELET), Wiegm. Archiv, 1837, 284, 

 Pisum maculatum, DESHAYES, Brit. Mus. Cat. 1854, 283. 

 Pisum bahiense, DESHAYES, loc. sub. cit. 1854, 284. 

 Musculium bahiense, ADAMS, Rec. Gen. II, 1858, 451. 

 Musculium maculatum, ADAMS, loc. sub. cit. II, 1858, 451. 



This, the smallest species of Spliserium, has the peculiar appear 

 ance characteristic of the West Indian and South American shells 

 of this genus. It does not seem to be uncommon. Some authors, 

 led away by its diminutive size, have committed the error, as may 

 be seen by the above synonymy, of placing it under the head of 

 Pisidium. I have never seen C. maculata, Anton (non More- 

 let), but have every reason to believe, from the description given 

 of it, that it does not differ materially from this species. In out 

 line it is somewhat similar to S. barbadense ; it is, however, 

 much smaller, less inflated, and the beaks are much more raised. 

 Compared with $. meridionale, and S. maculatum of Morelet, it- 

 is smaller, more inflated, and the margins are more rounded. 



32. Sphaerium &quot;barbadense, PRIME. Animal not observed. 

 Shell small, rounded oval, ventricose, subequilateral, delicate ; anterior 



side a little the shorter and narrower ; margins generally rounded ; beaks 

 slightly inclined towards the anterior, nearly central, small, calyculate, 

 approximate at apex, at times eroded ; striae coarse for the size of tho 



