VALVATA., 145 
Canon Norman is of opinion that this species is identi- 
cal with the Paludina crystallina of Pfeiffer, a West 
Indian species, and a few specimens he kindly sent me 
for inspection, bear a close resemblance to our species. 
Mr. E. A. Smith, however, 1s by no means convinced of 
this identity, as in his opinion the thread-like keel round 
the whorls of our British species differs from the carination 
of Pfeiffer’s P. crystallina var. coronata, which consists of 
a row of spines forming a coronation rather than a 
carination. 
Mr. Smith also informs me that Paludestrina candeana 
D’Orbigny, and Paludina cisternicola and ornata Morelet, 
also belong to this species according to Von Martens. 
Shuttleworth and Frauenfeld also state that Paludina 
jamaicensis and Melania spinifera, both of C. B. Adams, 
are also of this species. 
Microscopical examination of the radule of P. crystal 
lina and P. jenkinsit by the Rev. Prof. Gwatkin, shows the 
two to be similar, though this in itself, according to Mr. 
Gwatkin, is not positive evidence of identity, as ‘different 
species may have a similar radula.” 
Var. carindta (Smith). With a thread-like keel in the 
centre of the whorls. Found in all cases with the type, 
and in about equal proportion to it. 
Famtily.—V ALVATIDE. 
Genus.—VALVATA Miller. 
Eyes nearly sessile ; opercelum horny and thin. 
