1927] Pilsbry-Bequeart, The Aquatic Mollusks of the Belgian Congo 123 
Planorbis tanganyikanus Bourguignat. Grrmarn, 1908, ‘Rés. Scientif. Voy. 
Afrique Foa,’ p. 636. 
Planorbis sudanicus var. magna R. Srurany, 1894, in O. Baumann, ‘Durch 
Massailand zur Nilquelle,’ p. 310, Pl. xxtv, figs. 10, 14, and 29 (type locality: Lake 
Manyara, Tanganyika Territory). 
Planorbis sudanicus major E. v. Martens, 1897, ‘Deutsch Ost Afr., IV, Be- 
schalte Weichth.,’ p. 146 (described from several localities in East Africa, from Tan- 
ganyika, Lake Hdwandl and Lake Albert). 
Lake Tanganyika: originally described from near the outlier of the Lukuga River, 
and near the mouth of several streams on the western coast, such asthe Mkulungulu, 
Luandazi, and Mahongolo. Lake Edward: Kiruwe; Vichumnb: ; subfossil at Kata- 
renge (Stuhlmann Coll.). Lake Albert: (Stuhlmann Coll.). 
Lake Tanganyika: swamp in the plain of St. Louis de Mrumbi, 
on the western shore (Stappers Coll.). Lake Edward: on the shore at 
Kabare (J. Bequaert Coll.). Ngombe River, an affluent of the Lungat- 
shimo (H. Schouteden Coll.). 
This form resembles the type except in size. The specimens all 
show more or less minute spiral striation, either on both sides or on 
the left side of the spire only, a character we have not seen mentioned for 
the species. Some of the specimens from Lake Edward have numerous 
opaque rays on the last whorl. The concavity of the left side is sometimes 
so deep that the right side is flat with a very small central cavity. 
Usually the depth of the concavity is nearly equal on the two sides. 
Diameter, 17. mm.; altitude, 4.9 mm.; 5% whorls. 
” 15.5 ” 5 5: ” 
Other Species of Planorbis, proper, Recorded from the Belgian Congo 
Planorbis lavigerianus Bourguignat 
Planorbis lavigerianus BourGuIGNAT, 1888, ‘Iconogr. Malacol. Tanganika,’ PI. 
1, figs. 5-8; 1890, Ann. Sc. Nat. Zool., (7) X, p. 19, Pl. 1, figs. 5-8. E. v. Martens, 
1897, ‘Deutsch Ost Afr., IV, Beschalte Weichth.,’ p. 148. E. A. Smrru, 1904, Proce. 
Malacol. Soc. London, VI, 2, p. 98. ANcry, 1907, Bull. Scientif. France et Belgique, 
(5) TX, (1906), p. 249. 
Lake Tanganyika: southern coast of the Ubuari Peninsula near Kibanga (type 
locality). 
Planorbis monceti Bourguignat 
Planorbis monceti BourGuIGNnat, 1890, Ann. Sc. Nat. Zool., (7) X, p. 18. E. A. 
Smiru, 1904, Proc. Malacol. Soc. London, VI, 2, p» 99: eres 1907, Bull. Scientif. 
France et Belgique, (5) IX, (1906), p. 249. 
Lake Tanganyika: ENTS described from ce western coast of the lake, with- 
out more definite locality. J. Thiele (1911, ‘Wiss. Ergebn. D.Z. Afr. Exp. (1907-08),’ 
III, p. 209) states that a specimen from the falls between Lakes Bolero and Luhondo 
in Ruanda (Schubotz Coll.) was shaped somewhat like P. moncetv. 
