37. ZOOLOGICAL RESULTS OF THE PERCY SLADEN 
TRUST EXPEDITION TO YUNNAN UNDER THE 
LEADERSHIP OF PROFESSOR J. W. GREGORY, 
F_R.S. (1922). 
AQUATIC GASTROPOD MOLLUSCS. 
By N. Annanpvarn, D.Sc., F.B.S., F.A.S.B., CLE, Loological 
Survey of India. 
(With Plate 17). 
The collection of aquatic snails made by Professor Gregory 
and his son in Western Yunnan is even more interesting than 
that of land snails, for it includes numerous specimens (both 
called Lake Tali, which contains one of the most interesting 
lacustrine faunas known. It so happens that the Indian 
including those described in this aper. Those of which the 
names are marked with a star are represented in the Gregory 
collection. I have not been able to recognize with certainty 
all the Viviparidae described by Heude, but all are probably 
forms of the species discussed here. 
