230 Bulletin American Museum of Natural History [Vol. LIII 
3.3 mm.; aperture 3.0 mm. long; 10 whorls remain, apparently about one 
being lost. 
In a series from Sumbu Bay (Figs. 26b-g and 27a) the size is smaller 
and the whorls slightly more convex. In some examples the outlines of . 
the spire are about as in typical lacustris, while in others they are straight. 
The parietal callus is thicker, with raised edge. 
Length, 9.0 mm.; diameter, 3.0 mm.; length of aperture, 2.7 mm.; 11 whorls, 
apex entire. Po 
Length, 9.0 mm.; diameter, 2.80 mm.; length of aperture, 2.5 mm.; 8 whorls, 
apex lost. 
Length, 8.5 mm.; diameter, 3.00 mm.; length of aperture, 2.4 mm. 
Length, 9.2 mm.; diameter, 2.75 mm.; length of aperture, 2.6 mm.; 10 whorls, 
the tip lost. 
sits 
a 
Fig. 27. Syrnolopsis lacustris E. A. Smith: a, Sumbu Bay; 0, profile of one 
of the original lot. c-d, Syrnolopsis lacustris molirensis, last whorl. 
In these specimens, which clearly are fully adult, the outer lip is 
obtuse and slightly expanded, the basal lip effuse and somewhat re- 
curved. All of them are typical in the columellar fold. A specimen 
similar to Fig. 26c opened shows the columellar lamella distinctly in the 
lower four whorls, hardly a trace of it in the next earlier and none in those 
above. In the sixth from last whorl there is a shelly partition across the 
cavity (Fig. 27a). Another shell opened, similar to Fig. 26b, shows the 
columellar lamella in the last two whorls only (Fig. 26e). The section 
figured by Smith shows the columellar lamella ascending farther than in 
those we have opened, if the early whorls are drawn correctly, which is 
open to doubt. 3 | 
Young examples of about six and eight whorls (Fig. 26d) have the 
columella straight and foldless. : 
Charles Hedley found this species more abundant than any other 
of the family on the sandy beach at Albertville. 
