1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 119 
Height, 5.0 mm.; diameter, 12.0 mm. 
Bae oe 8 be 16.2. Irumu. 
Germain has discussed the relationship of this species to P. bridoux- 
vanus, stating that some specimens approach it rather closely. On the 
other hand, some large adowensis resemble P. sudanicus tanganikanus. 
Planorbis bridouxianus Bourguignat 
Planorbis bridouxianus BourGuiIGNAT, 1888, ‘Iconogr. Malacol. Tanganika,’ 
PI. 1, figs. 9-12; 1890, Ann. Se. Nat. Zool., (7) 2, p. 20, Pl. 1, figs. 9-12. E. v. Marrens, 
1897, ‘Deutsch Ost Afr., IV, Beschalte Weichth.,’ p. 149. E. A. Smrru, 1904, Proce. 
Malacol. Soc. London, VI, 2, p. 98; 1909, Trans. Zodl. Soc. London, XIX, 1, p. 47. 
ANCEY, 1907, Bull. Scientif. France et Belgique, (5) IX, (1906), p. 249. J. Ture.s, 
1911, ‘Wiss. Ergebn. D. Z. Afr. Exp. (1907-1908),’ III, p. 209. 
Planer bridouxt form ortentalis GERMAIN, 1904, Bull. Mus. Hist. Nat. Paris, 
p. 350, footnote (Lake Tanganyika). . 
Plavionees bridouxi Bourguignat. GERMAIN, 1905, Bull. Mus. Hist. Nat. Paris, 
p. 256; 1908, ‘Rés. Scientif. Voy. Afrique Foa,’ p. 636. 
Planes: (Planorbis) bridoux1 Bouneutennt, GERMAIN, 1921, Ree. Indian Mus., 
AXI, p. 25. 
Lake Tanganyika: mouth of the Mahongolo River near Kibanga, on the western 
shore (type locality). Mt. Ruwenzori (Woosnam Coll.). Also recorded by Thiele 
with some doubt from Lake Mohasi in Ruanda (Schubotz Coll.). 
Aruwimi River in the rapids of Mombitili, above Bomili, a6 XII- 
1918; Lake Edward at Kabare (J. Bequaert Coll.). 
Near P. adowensis, but smaller, the whorls increasing more rapidly, 
the last one wider. Microscopic spirals are visible on the left side, as in 
related forms. A specimen from the Aruwimi measures: diameter, 7.5 
mm.; altitude,3.2mm. * | 
A series from Lake Edward consists of specimens with the aperture a 
little smaller. One of the largest measures: diameter, 8 mm.; altitude, 
3.1 mm. 
8 
Planorbis bridouxianus var. foat (Germain) 
Planorbis bridouxi var. foat GERMAIN, 1904, Bull. Mus. Hist. Nat. Paris, p. 351, 
footnote; 1905, op. cit., p. 256; 1908, ‘Rés. Scientif. Voy. Afrique Foa,’ p. 637. 
Lake Tanganyika: at the southern end (Foa Coll.). 
Planorbis choanomphalus E. v. Martens 
Text Figure 5 3 : 
Planorbis choanomphalus BE. v. Martens, 1879, Sitz. Ber. Ges. Naturf. Fr. 
Berlin, p. 103 (type locality: southwestern shore of Lake Victoria); 1897, ‘Deutsch 
Ost Afr., 1V, Beschalte Weichth.,’ p. 148, Pl. vi, figs. 14 and 15. Germain, 1905, Bull. 
Mus. Hist. Nat. Paris, p. 256; 1908, ‘Rés. Scientif. Voy. Afrique Foa,’ p. 637. J. 
THIELE, 1911, ‘Wiss. Ergebn. D. Z. Afr. Exp. (1907-08),’ IIT, p. 209. 
