294 THE CHICAGO ACADEMY OF SCIENCES. 
the side of an aquarium, eating everything in its path. Ifa 
morsel that is distasteful is taken into the mouth, it will be 
immediately “spit out.” In one specimen examined, the man- 
tle cavity was infested by a small parasite (or messmate) 
which came out and went into the mantle chamber without 
causing the snail any apparent discomfort. Azcarinatus is found 
in all regions of the area, and has been collected fossil in sand 
banks on the lake shore, north of Graceland avenue, by Mr: 
Jensen. 
SuBGENUS PLANORBELLA Haldeman, 1844. 
‘Shell few-whorled, aperture campanulate.” (Dall.) 
117. Planorbis campanulatus Say, pl. xxxii, fig. 11. 
Planorbis campanulatus SAy, Jour. Phil. Acad., Vol. II, p. 166, 1821. 
Planorbts bellus LEA, Proc. Amer. Phil. Soc., Vol. II, p. 32, 1821. 
Planorbts bicarinatus SOWERBY, Genera, pl. iv (non Say). 
Helix angulata SHEPPARD, teste J. de C. Sowerby, Fauna Boreali- 
Americana, Vol. III, p. 315. 
Planorbis campanulatus minor CURRIER, Walker, The Nautilus, Vol. 
VI, p. 187. 
13 
y, ; 
Fre. 98. 
Radula of PLANGRBIS CAMPANULATUS Say. (Original.) c, central be 
tooth; 1, first lateral; 9, intermediate tooth; 15, third marginal. | 
Shell: Sinistral, discoidal, more or less rounded; color 
brownish-horn, sometimes reddish; surface shining, lines of 5 
growth oblique, very numerous, raised, equidistant for the 
most part; whorls four, discoidal. rounded above and below, , 
rarely subcarinated; spire flat, on a level with the general plane 
ot the whorls, exhibiting all the volutions; sutures deeply im- 
pressed; periphery rounded; base of shell rounded, showing 
two volutions with a deep umbilicus in the middle; aperture Lg 
