1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 113 
nected spots in the region over the lung. The foot is vere shades of 
slate. 
The genitalia (Fig. 2a-c) are mainly characterized by the very 
slender upper sac of the penis, which is scarcely differentiated from the 
vas deferens. The prostate gland is club-shaped. These are characters 
of the subgenus Radix. Other characters are sufficiently shown in the 
figures. 
The radula (Fig. 3) has about nine lateral teeth, having a bifid 
inner cusp (entocone and mesocone) and a small outer cusp. The 
marginals are oblique, with either three or four denticles. 
Eig: 3. Lymnexa natalensis undussumx. Teeth of a Kidada specimen. 
Other Forms of Lymnzxa Recorded from the Belgian ae 
Lymnzxa (Radix) anceyana (Preston) 
Limnzxa anceyana PRESTON, 1910, Ann. Mag. Nat. Hist., (8) VI, p. 59, Pl. rv, 
fig. 4. 
~* Pype locality: Maringo River, Belgian Congo. Noriver of that name is known 
to us in the Belgian Congo. | 
This appears to be a synonym of L. natalensis undussume (E. v. Martens), 
Lymnexa (Radix) carllauds (Bourguignat) 
Limnea caillaudi BouRGUIGNAT, 1888, Ann. Sc. Nat. Zool., (6) XV, p. 89, Pl. x, 
figs. 100-101 (type locality: Lake Dembea [Tsana], Abyssinia). 
Limnexa acroca Bourcuienat, 1888, Ann. Sc. Nat Zool., (6) XV, p. 90, Pl. x, 
fig. 94 (type locality: Blue Nile below Lake Dembea, sane 
_ Limnea africana “Ruppell” Boureurienat, 1883, Ann. Sc. Nat. Zool., (6) XV, 
pp. 95 and 126, PI. x, fig. 99 (type locality: Lake Denben. Ayden $ 1590; C11. ; 
(7) X,p.10. Ancry, 1907, Bull. Scientif. France et Belgique, (5) IX, (1906), p. 249. 
Germain, 1919, Bull. Mus. Hist. Nat. Paris, p. 185; 1920, Voyane dans |’ Afrique 
Orientale Anglaise (1912-1913) par G. Babault, moths Terr. Fluv.,’ PR 141 and 185, 
figs. 831-49, 56-59, Pl. rv, figs. 6-11. 
as. alecandrina BouRGUIGNAT, 1883, ak: Se. Nai Zool., (6) XV, p. 92, Pl: 
x, figs. 95-96 (type locality: Blue Nile, ea 1890, op. cit. (7) a8: ANCEY, 
1907, Bull. Scientif. France et Belgique, (5) IX, (1906), p. 249. 
_ Limnexa kynganica Bourcuienat,, 1889, ‘Moll. Afrique Equator.,’ p. 158 (type 
locality: valley of the Kingani River, south of Bagamoyo, Tanganyika Territory). 
- Limnea laurentti Bourcutenat, 1883, Ann: Se: Nat. Zool., (6)-XV, p. 88 (nomen 
aa 1888, ‘Iconogr. Malacol. Taneaniken? Pl. 1, figs. 21-22: 1980, Ann. Sc. Nat. 
