THE APPLE-SNAILS OF SIAM. 11 



Burma and its range extends to China. Blanford records it from 

 Pitsanuloke. 



Pachylabra gracilis (Lea). 



1856. Ampullaria gracilis, (Lea), Proc. Ac. Nat. Sci. Philadelphia, 



VII, p.110. 

 ? date. Ampullaria gracilis, id., Ohs. Genus Unio, etc. XI, p.70, 



pi. xxii, fig. 1. 



Lea's figure and descriptions are probably based on 

 a young shell, and the only specimen I have seen also seems 

 young. The adult shell may be identical with one of those figured 

 by Kobelt (op. cit., pi. xxxvii, fig. 4) as shells of P. dalyi ; but this 

 figure certainly does not represent either that race or any other of 

 P. turbinis. The specimen I have examined resembles a young 

 shell of P. conica, but is longer in proportion, with a longer and 

 narrower mouth, a more exserted spire, a more even surface and 

 more conspicuous external spiral bands. The lip is also more 

 sinuous and more produced at the anterior end. The sculpture con- 

 sists of fine longitudinal ridges with obsolete longitudinal and spiral 

 striae. 



The following are the measurements and proportions of this 

 shell : — height 35, maximum diameter 29, height of mouth 25, 

 maximum diameter of mouth 11 mm. Proportion of maximum 

 diameter to height of shell 1 : 1.2, height of mouth to that of shell 

 1 : 1.4, maximum diameter to height of mouth 1 : 2.26, maximum 

 diameter of mouth to that of shell 1:2.63. 



This shell is labelled "Siam" and the species was described 

 without any more precise locality. Blanford records it from Lam- 

 pun in the northern part of the Kingdom. 



Pachylabra angelica, sp. nov. 

 The shell is large, of moderate thickness and in shape inter- 

 mediate between P. polita (Desh.) and P. turbinis (Lea); it is much 

 more globose than the former but has a whorl more than the latter, 

 than which also it is slightly more elongate. Its total height is a 

 little greater than its maximum diameter. There are 6£ whorls, 

 and the spire, though almost acuminate, has a globose appearance 

 towards the base, with somewhat swollen whorls. The extent to 



VOL. IV, NO. 1, 1920. 



