1927] Pilsbry-Bequaert, The Aquatic M onesie of the Belgian Congo 191 
bounded by a distinct wean in the upper whorls, but this is obsolete on 
the last. The glossy surface is smoothish except for lines of growth, but 
sometimes faint spiral strie are traceable in places. The color is chamois 
or more olivaceous, with chestnut-brown or olive bands. The quite 
oblique aperture is rather wide. Columella moderately white-calloused. 
Adnate part of the inner lip rather short. The upper whorls are always 
eroded, more or less. 
Length; 24.0 mm., . diameter, 29.0 mm.; aperture, 19X13.5 mm. Stanloyville 
es 25.0 as 26:5 Stanleyville. 
c4 19.0 oy 20.0 Between Ankoro and Kikondja. 
The spire is never so deeply eroded as in L. graweri, which lives 
associated with nsendweensis in some places. In some young examples, 
8 to 10 mm. in diameter, the strongly convex initial whorl is seen to be 
very minutely pitted. | 
The form is always more depressed than in L. libycus (Morelet), 
from which the absence or very slight development of spiral sculpture 
also separates it. In quite young shells, of about 12 mm. diameter, 
the length and diameter are equal, but in later stages the diameter 
increases faster than the length. The flat zone along the suture is 
narrower than in L. congicus, and its bounding angle is far less strongly 
developed, being sharp only in the earlier stages of growth. 
L. nsendweensis appears to be a common and generally distributed 
species of its region. 
‘These snails were numerous in the Congo River near Stanleyville 
about the rocky portions below the falls (Pl. LXIV, fig. 1), where in the 
many quiet stretches they are sheltered from the direct influence of the 
current. Also found in some of the smaller forest affluents and a few 
swampy places near the river.” (H. L.) ‘ 
- Lanistes nsendweensis katanganus, new subspecies 
Plate XVIII, Figure 11 
Little Lubembe River in Upper Katanga (J. Bequaert Coll.). These 
specimens were recorded under the name ‘‘ Lanistes bourguignont Put- 
zeys”’ by Dautzenberg and Germain (1914, Rev. Zool. Afric., IV, 1, p. 
51). | | 
The shell resembles L. nsendweensis in miniature. There is an angle on the 
second whorl, weakening on the third, and absent on the last whorl, in which the 
subsutural flattening is rather indistinct toward the end. The narrow umbilicus has 
no trace of a bordering angulation. The first whorl is strongly convex, with a beauti- 
ful, close, pitted sculpture. 
Length, 15.3 mm.; diameter, 17 mm.; 4% whorls. 
