112 Bulletin American Museum of Natural History [Vol. LITI 
geen numerous specimens from Kibwezi, Kenya Colony (Dammer Coll.). 
Specimens from the Lubumbashi River (J. Bequaert Coll.), referred by 
Dautzenberg and Germain to exserta (v. Martens), are also in our opinion 
UNAUSSUME. 
Very fragile shells, olive-buff to cream-buff in color, or rarely vina- 
ceous-cinnamon, the axis closed or very narrowly open. Shape variable, 
but typically ovate with full outline. The degree of inflation of the upper 
part of the last whorl is individually variable in every lot of several speci- 
mens, the angle formed by the outer lip at its insertion, and the shape of 
Fig. 2. Lymnexa natalensis undussume v. Martens. 
a, genitalia of specimen from Kidada: 0, oviduct; pr, prostate gland; s, spermatheca; <’, penis- 
b, pene, pulled nearly straight. c, outline of ‘prostate gland i in profile. 
the aperture consequently variable individually in most lots. The 
inflation of the last whorl increases with age, but varies widely in degree 
at all ages, as in the selected series of Pl. XI, figs. 1 to If, from a large lot 
taken in the Lubumbashi River, and consisting largely of specimens 
intermediate in shape. It will be seen that this series runs from the 
typical undussumex shape to that of L. natalensis exserta (v. Martens). 
Less variation was noted in specimens from Irumu, PI. ‘XI, figs. 2-2c, 
and in those from Faradje, Pl. XI, figs. 5 to 5b. 
K. v. Martens based his L. humerosa on a more shouldered ex- 
ample, such as Pl. XI, fig. 4, from Moto (Burgeon Coll.). 
Length, 20.0 mm.; diameter, 12.0 mm.; length of aperture, 15.5 mm.; Faradje. 
ERA ost re ea pte eet 
The mantle is black with white specks or spots. In some of the 
specimens from Kidada the black is reduced, forming partially con- 
