THE APPLE-SNAILS OF SIAIVL 17 



Measurements (in millimetres) and Proportions of Shells. 



Height 70 



Maximum diameter 70 



Height of mouth 57 



Maximum diameter of mouth 31 



Maximum diameter to height 1 : 1 



Maximum diameter to height 



of mouth 1 : 1.84 



Mouth to height 1 : 1.22 



Max. diam. of mouth 



to maximum diameter 1 : 2.22 1 : 2.41 1 : 2.19 



The height and the maximum diameter of the shell are thus 

 practically the same, the mouth nearly twice as high as broad and 

 r ather more than •£ as high as the whole shell, which is from 2-=- 

 to 2| as broad as it is high. 



There is no information available as to the precise habitat of 

 this race. Lea merely says "Siam," and Nevill's specimens, with 

 one exception, appear to have been originally labelled "Java", but 

 he was probably right in believing that they were of Siamese 

 origin. There is a young shell from Cambodia in the collection of 

 the Indian Museum, but whether it belongs to this race is uncertain. 

 It is considerably broader in proportion than young shells of the 

 race subampullacea. 



Race dalyi (Blanford). 



1902. Ampullaria dalyi, Blanford, Proc. Malac, Soc. London, Y, 



p. 281, pi. viii, fig. 1. 

 1911. Pachylabra dalyi, Kobelt (in part), op. cit., supra, p. 80, pi. 



xxxix, fig 1. 

 1911. Pachylabra turbinis, id., ibid., pi, xxxvii, figs. 1,2. 



I think that Blanford was right in. suggesting that this was 



only a race of* P. turbinis. The shell is distinguished by its 



coarser, thicker, still more globose character and larger maximum 



size. The upper part of the mouth projects less in ventral view, 



but its maximum diameier is greater, and the base of the body-whorl 



is channelled just below the botly-whorl. The shape of the spire 



varies considerably. In some specimens it is considerably more 



VOL. IV, NO. 1, 102O. 



