1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 281 
The color is between honey-yellow and isabella, becoming lighter ecru- 
olive or old gold on the spire, and more brownish toward the base. | 
Length, 34.5 mm.; diameter, 13.5 mm.; 544 whorls remaining. 
paren - 13.3 nearly 4 whorls remaining. 
Many specimens from the Nepongi River, at Panga (Pl. X XVI, 
figs. 8-8c) are smaller than those of Medje, varying in spiral ribs from 
six to one on the last whorl as shown-in the figures. The color is chest- 
nut at the base, fading to ecru-olive on the early whorls. | 
Length, 32.7 mm.; diameter, 12.0 mm.; 6 whorls remaining. 
geting th * 12.3 tea 
Potadoma liricincta major (J. Thiele) 
Plate XX VI, Figures 5 and 5a 
Melania liricincta var. major J. Tuieue, 1911, ‘Wiss. Ergebn. D. Z. Afr. Exp. 
(1907-08), Tid; pelt, Phy oe se. 
Between beni aa Boga (type locality; Schubotz Coll.). 
Among the forty-four specimens from Medje referred to liriconcta, 
fifteen belong to a smooth form. In a few of these some extremely faint 
traces of spirals are discernable in the peripheral region. Under a strong 
lens a minute, wavy spiral lineolation is visible in places, chiefly on 
the upper whorls. In this it differs from lirate liricincta, which only 
occasionally shows very imperfect traces of such lines. These specimens 
appear to be referable to Thiele’s var. major, which came from the 
western border of the Semliki watershed. 
Potadoma liricincta walikalensis, new subspecies 
Plate XX VI, Figure 9 
In a forest brook flowing to the Lubutu River, at Managembi, 30 
miles east of Lubutu (J. Bequaert Coll.). : 
Stout specimens from this locality have strongly raised spirals, usually nine on 
the last whorl. A plain zone below the periphery is seen in one of the eleven examples. 
This place is in the Lowa drainage, and must be close to the type locality of var. 
latior Thiele, which has the spiral cords less developed. If varieties are definable in a 
mutation series so variable, these specimens may be considered fully sculptured latior. 
In old specimens the color is a little browner throughout then in Medje liricincta, 
when the black coat is removed. 
Length, 31.0 mm.; diameter, 15.3 mm.; 3 whorls remaining. 
AY yA se 14.7 2 eee 4 
ee 4 13.3 about 444 whorls remaining. 
