1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 351 
Pisidium landeroint GeRMAIN, 1909, Bull. Mus. Hist. Nat. Paris, p. 476; 1911, 
‘Doc. Scientif. Miss. Tilho,’ II, p. 218, Pl. m1, figs. 32 and 33. Between Uani and 
Hangara, in the Eguei District, east of Lake Chad. 
Pisidium langleyanum MEtvitt AND PonsonsBy, 1891, Ann. Mag. Nat. Hist., 
(6) VIII, p. 237; 1892, op. cit., (6) IX, p. 94, Pl. v, fig. 7. Port Elizabeth. 
Pisidium ovampicum Ancry, 1890, Bull. Soc. Malacol. France, VII, p. 162. 
Omambonde, Ovampoland. This is, aecording to Connolly, possibly the species re- 
corded by Beettger (1910, Abh. Senckenberg. Naturf. Ges., XXXII, p. 455, PI. 
XXvill, fig. 19) as related to P. langleyanum and found subfossil at Witkop, British 
Bechuanaland. 
Fig. 76. Pisidium kenianum Preston. 
Pisidium pirotht Jickrut, 1881, Jahrb. Deutsch. Malakoz. Ges., VIII, p. 340 
Harasa, between Atbara and Bassalam, Abyssinia. 
Pisidium ruwenzoriense GERMAIN, 1911, Bull. Mus. Hist. Nat. Paris, p. 135. On 
the eastern slopes of Mt. Ruwenzori in Uganda; in the lower zone in an affluent of 
the Wimi River and at the foot of the Kichuchu rock-shelter in about 3,000 m.; 
also on Mt. Kilimanjaro in 2,200 m. (all C. Alluaud Coll.). This will undoubtedly 
be found on the western slope of Mt. Ruwenzori, in Belgian territory. It is the largest 
African species yet known, measuring: length, 5.5 mm.; height, 4.5 mm.; diameter, 
3mm. The lateral teeth are said to be much lengthened. 
Probably the clam described as Spherium kigeziense Preston will turn out 
to be a Pisidium. 
