sni^RiuM. 53 



c. Shell always small, ehomboidal, beaks calyculate. 



31. Sphaei'iimi l>aliieiise, Spix. — Animal not observed. 



Shell very small, rounded-oval, inflated, inequi- 

 lateral ; anterior margin narrow, curved ; posterior ^%* ^2. 

 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 hahiense. 

 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 Baliia in Brazil. (Cabinets of Jay, Prime and 

 others.) 



Cyclas bahiensis, Spix, Test. Braz. 1827, 32, pi. xxv, f. 5, 6. 

 Cyclas macuJata, Anton (non Mokelet), Wiegm. Archiv, 1837, 284. 

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

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

 MuscuUum bahiense, Adams, Rec. Gen. II, 1858, 451. 

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



This, the smallest species of Spheey^ium, 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 G. 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 S. meridionaJe, and S. macidatum of Morelet, it 

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



32. SpliaeriuMi l)arl>adense, Pkime.— 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 ; striie coarse for the size of the 



