1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 219 
Length, 4.4 mm.; diameter, 4.0 mm.; length of aperture with peristome, 3.0 mm.; 
4 whorls. 
Length, 2.9 mm.; diameter, 2. 8mm.; length of aperture with peristome, 2.3 mm.; 
3% whorls. 
The thin operculum lodges in a vertical position, with the lower 
margin just within the lip-edge, the upper much farther in. The nucleus 
is near the lower third of the length. There are 1% spiral whorls, the 
last half-whorl enlarging very rapidly. This is surrounded by a band of | 
concentric increment, the width of which is from somewhat less than one- 
fourth the width of the operculum to, in the largest examples, nearly a 
third its width. Internally it has an extremely thin calcareous layer, a 
little roughened and slightly concave in the middle, thin toward the 
edges. ; 
The small number of whorls and their rapid increase, the last one 
expanding, somewhat campanulate at the mouth, and the large, rather 
strongly oblique aperture, are diagnostic of this species. — 
The very superficial spiral striz are present only on the best pre- 
served examples. Smith did not mention them. The size of fully adult 
shells with thick, expanded lip varies considerably. 
Fig. 19. Bulimus humerosus (E. v. Martens). Kisumu, Lake Victoria. 
Other Species of Paranerita (?) Recorded from the Belgian Congo 
Bulimus (Paranerita) humerosus (E. v. Martens) — 
Text Figure 19 
Bithynia stanleyt var. humerosa E. voN Martens, 1879, Sitz. Ber. Ges. N tus: 
Fr. Berlin, p. 104 (type locality: southwestefn shore of Lake Victoria). 
Bithynia (Gabbia) humerosa E. v. Martens, 1897, ‘Deutsch Ost Afr., IV, 
Beschalte Weichth.,’ p. 190 (fig.of radula ), Pl. v1, fig. 31. 
Bythinia (Gabbia) humerosa E. v Martens. German, 1916, Bull. Mus. Hist. Nat. 
Paris, p. 200. 
valle Edward: E. v. Martens in 1897 refers to this species, with some sane 
subfossil specimens obtained at Vichumbi by Stuhlmann. All Bulimus collected by 
