280 Bulletin American Museum of Natural History [Vol. LIII 
lip thin, very slightly sinuous; columella and basal lip calloused within. Parietal 
wall covered with a thin, dark colored callus. 
Length, 24.3 mm.; diameter, 9.3 mm.; length of aperture, 8.7 mm.; 7}4 whorls 
remaining. ‘Type. 
This form is closely related to M. lricincta and may possibly prove 
to be a subspecies of that polymorphic species. It differs by the small 
size and slender form, by the absence of cords in the columellar region 
and by retaining most of the whorls. Its minute sculpture also differs. 
From a study of long series of both forms we believe them specifically 
distinct. Unlike lirzconcta, the sculpture seems quite constant in pokoen- 
sts; but as yet it is known from a single station. 
Potadoma liricincta (HK. A. Smith) 
Plate XX VI, Figures 4—4b, 6, and 8-8c 
Melania (Melanoides) liricincta Eh. A. Smiru, 1888, Proc. Zool. Soc. London, p. 53, 
fig. 1. E. v. Martens, 1897, ‘Deutsch Ost Afr., 1V, Beschalte Weichth.,’ p. 195. 
‘Lake Albert’ (type locality; Emin Pasha Coll.). 
Medje, 44 specimens (Lang and Chapin Coll.). Panga, in the 
Nepongi River, an affluent of the Ituri (J. Bequaert Coll.). 
This species is spread, in a great variety of mutations and local 
forms, in the upper Ituri and its tributaries, southward in some tribu- 
taries of the Lualaba, and eastward in tributaries of the Semliki. The 
type was supposed to be from Lake Albert, collected by Emin Pasha; 
but Stuhlmann and others have not found this species in the lake. 
Probably the type was picked up in some stream westward or south- 
west of the lake, in the area where we know that this river melanian 
occurs. 
The type was described as having two or three cords around the 
lower part, and other specimens are said to have ‘four round the middle 
part of the body-whorl and four at the base, the two sets being separated 
by a smooth blank space.’”’ The dimensions are given as length, 26.0 
mm.; diameter, 9.5 mm.; length of aperture, 9.5 mm.; 5 whorls remain- 
ing. The original figure is reproduced, Pl. XXVI, fig. 6. 
The form from Medje (Pl. XXVI, figs. 4—4b) is practically typical 
in sculpture, but larger than Smith’s type. There isa group of about four 
spiral cords at and above the periphery, followed by a plain space, then 
two or three small cords around the columella. Two or three of the 
spirals ascend on the lower half of the penult and antepenult whorls in 
some examples, not so far in most, leaving the earlier whorls plain except 
for a carina barely visible above the suture, and faint growth-lines. 
