90 On new Shells from West Africa. 



anteriorly; dorsal margin sloping; ventral margin nearly 

 straight ; anterior side flattened, rounded ; posterior side 

 tumid, somewhat rostrate, sloping above, rounded below ; 

 interior of shell pale livid flesh-colour. 



Long. 35, lat. 88 mm. 



Hah. Gaboon. 



SpatJia semicorritgata, sp. n. (Fig. 7.) 



Shell oblong, solid, covered with a blackish-brown peri- 

 ostracum which is minutely wrinkled posteriorly, sculptured 

 with rather coarse concentric lines of growth and corrugated 

 on the upper portion of the posterior side; umboes small, 

 situated somewhat anteriorly ; ligament elongate, not promi- 

 nent ; dorsal margin slightly arched posteriorly, sloping 

 anteriorly ; ventral margin nearly straight ; anterior side 

 Jingled, bluntly acuminate ; interior of shell rosy pink, 

 iridescent, especially towards the margins. 



Long. 51*5, lat. 87 mm. 



Hah. Lower Congo. 



Corhi'cula gabonensis, sp. n. (Fig. 8.) 



Shell rotundly trigonal, somewhat inflated, chalky white, 

 covered with a fine, polished, smooth, olive-green peri- 

 ostracum, sculptured with regular, somewhat distant, con- 

 centric ribs ; umboes livid purple ; ventral margin gently 

 rounded ; anterior side bluntly rounded ; posterior side very 

 slightly produced, rounded ; cardinal teeth two in each valve, 

 rather coarse ; lateral teeth elongate, serrated ; interior of 

 shell livid purple. 



Long. 22, lat. 23'25 mm. 



Bah. Gaboon. 



Oalatea ruhrotincta, sp. n. (Fig. 9.) 



Shell subtrigonal, white, covered with a smooth brownish- 

 olive periostracum, occasionally spotted with umber-brown 

 and tinged, especially anteriorly, with rusty red, smooth, 

 posteriorly radiately grooved, bearing a lunule on either side ; 

 umboes large and prominent ; anterior side steeply sloping 

 above, sharply rounded below ; posterior side concave, 

 abruptly sloping above, bluntly rostrate below ; ventral 

 margin gently rounded ; teeth large, coarse, finely granular, 

 somewhat lacerated, especially on the right valve ; interior 

 of shell pure white. 



Long. '69, lat. 41 mm. 



Bub. Congo Delta. 



