THE APPLE-SNAILS OF SIAM- 15 



large broad opening. The lamellae of the gills also are well deve- 

 loped leaf-like structures. The ridge separating the branchial from 

 the lung portion of the respiratory cavity is particularly thick in 

 its anterior portion. The rectum is a very thick tube and the open- 

 ing of the anus is large. The sacs for the copulatory organs are 

 well developed. 



" The buccal mass is a massive structure with well developed 

 salivary glands lying just posterior to it ; the glands of the two 

 sides are unequal, that of the right side is larger than that of the 

 left, and is placed a little in front of it. The mouth is a large 

 vertical opening with thick lips on its two sides. The jaws are 

 large with a single cutting tooth developed on each. The radula and 

 the cartilaginous flaps on its sides are both brownish in colour. 

 The stomach has a small caecum. 



" There is nothing special to note regarding the vascular and 

 the excretory systems. The ovary is large and cut up into a 

 number of lobes. The albumen gland also is a large structure. The 

 male organs are similar to those of P. globosa," 



Pachylabra turbinis (Lea). 



1856. Ampullaria turbinis, Lea, Proc. Ac. Nat. Sci. Philadelphia 



VII, p. 110. 

 1860. Ampullaria celebensis, v. Martens (nee Quoy & Gaimard), 



Proc. Zool. Soc. London, p. 12. 

 1863. Ampullaria turbinis, Morelet, ' Ser. Gonchyl. Ill, p. 288. 

 ? date Ampullaria turbinis, Lea, Obs. Genus TJnio, etc., XI, p. 70, 



pi. xxii, fig. 2. 

 1884. Ampidlaria turbinis and var. subglobosa, Nevill, Rand List 



Moll. Lid. Mus. II, p. 6. 



1904. Ampullaria turbinis, Fischer & Dautzenberg, Et. div. Miss. 



Pavie Indo-Ghine III, p. 425. 



1905. Ampullaria turbinis and var. erythrocheila, Dautzenberg k, 



Fischer, Journ. de Gonchyl. LIII, p. 427. 

 1911. Pachylabra turbinis, Kobelt (in part), op. cit. , supra, p. 78, 

 pl.xxxvii, fig. 3. 



Lea's English description of the species, which seems to be 



the dominant one in Siam, is as follows : — 



" Shell turbinate, yellowish green, transversely banded, rather 



thick, scarcely perforate, smooth ; spire very much depressed : 



sutures slightly impressed; whorls about five, very convex; 



VOL. IV, NO. 1, 1!>20. 



