PHYSA. 161 
a. PHYSA OSCULANS, Haid. 
Hald. Monog. p. 29, t. 2, f. 13 (exel. f. 11, 12). 
This is certainly a Mexican, not an Indian 
species, and belongs to the genus Bulinus. 
6. PHYSA MEXICANA, Philippt. 
Plate 7, fig. 12. 
Shell imperforate, ovate, inflated, light horn 
color, thin, dull and not shining, very finely 
wrinkled ; the apical whorls occupy one-fourth 
of the entire length; mouth wide; columellar 
fold broadly expanded, almost in the centre of 
the aperture.—Binney. 
Length 19, diam. 12 mill. 
“This is a true Physa, and to it are referable 
specimens in the collection of the Academy at 
Philadelphia as well as in many public and 
private collections which have been labelled 
Ph. osculans on account of some resemblance 
to Haldeman’s figures 11 and 12 which are 
named osculans, but really represent hetero- 
stropha. 
(77) 
