1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 349 
| The examples which we have seen from Kiabwa on the Lualaba, 
Luebo on the, Lulua, and Moto, are referred to this species with some 
doubt, as.v. Martens’ small and unsatisfactory figure of the interior 
shows far stronger lateral teeth. This figure, however, is probably in- 
correct, as v. Martens says: ‘‘Schlosszahne sehr schwach.”’ 
The largest specimen, a complete one from Moto, measures: length, 
12.2 mm.; height, 10.3 mm.; diameter, 7.4mm. The striation is very 
fine, and, in suitable light, extremely fine, very superficial, closely crowded 
radial lines are seen to impress the strie slightly. The hinge-plate 
is very narrow; the cardinal teeth occupy its whole width. In the right 
valve the cardinal tooth is long, parallel to the hinge, its posterior limb 
abruptly deflexed and thickened. Lateral teeth are short, doubled; 
the anterior stronger than the posterior; the upper ones very small. In 
the left valve the anterior cardinal tooth is high, rather thick, oblong, 
the posterior slender and short. 
Fig. 75. Spherium stuhlmanni E. v. Martens’ Moto. a-6, left valve, c-d, 
right valve. 
Other Species of Sphxrium Recorded from the Belgian Congo 
Spherium capense (Krauss) 
Cyclas capensis Krauss, 1848, ‘Siidafrik. Mollusk.,’ p. 7, Pl. 1, fig. 6 (type locality: 
Knysna River, Cape Colony). J. Turete, 1911, ‘Wiss. Ergebn. D. Z. Afr. Exp 
(1907-08),’ III, p. 212. 
Lake Karago in Ruanda (Schubotz Coll.). Specimens from that locality were 
somewhat doubtfully referred to this species by J. Thiele. 
Spherium mohasicum J. Thiele 
Spheriwm mohasicum J. Taree, 1911, ‘Wiss. Ergebn. D. Z. Afr. Exp. (1907—08),’ 
Ill, p. 212, Revmeey. 
Lake Mohasi in Ruanda (type locality; Schubotz Coll.). 
“See 
