THE APPLE-SNAILS OF SIAM. 5 



P. gracilis (Lea) from " Siam " 



P. pesmei (Morlet) „ Srakao 



"P. polita (Deshayes) „ Chengmai 



P. turbinis (Lea) „ " Siam " 



The occurrence of P. borneensis [the synonomy of which is 

 still doubtful], of P. celebensis [=P. ampullacea (L.)] and of P. globosa 

 in Siam is most improbable. The two former are species found in 

 the Malay Archipelago and are known to have been often confused 

 with mainland forms. P. globosa is the common form in the valley 

 of the Ganges. The species here described as P. angelica may have 

 been confused with it. 



The late Dr. W. T. Blanford, who was well acquainted with 

 the Indian and Burmese species and varieties, recorded the following 

 species from northern Siam : — 



P. polita (Deshayes) P. gracilis (Lea). 



P. conica (Gray) P. dalyi Blanford. 



To these must be added the race describe;! by Nevill long pre- 

 viously as Ampullaria turbinis var., subampidlacea, and also a 

 second variety of the same species (lacustris) to be described here, a 

 hitherto unknown species for which I propose tha name P. angelica, 

 and, finally, the Cambodian species P. begini (Morlet). I regard P. 

 dalyi as a variety of P. turbinis. The following list of species, 

 varieties and localities embodies our present knowledge of the 

 geographical distribution of Siamese forms so far as that kingdom 

 is concerned : — 



P. polita. Bangkok & Chengmai (Fisch. & Dautz.) ; ? Upper 

 Menam (Blanford). 



P. conica. Pitsanuloke ; Lam pun (Blanford). 



P. gracilis. Lampun (Blanford). 



P. angelica. Bangkok. 



P. turbinis. " Siam". 



P. turbinis race dalyi. N. Siam (Blanford); Pitsanuloke. 



P. turbinis race subampullacea. Singgora and Patalung. 



P. turbinis race lacustris. Inner region of Inland Sea of 

 Singgora. 



P. begini. Lat Bua Kao, Korat. 



VOL, IV, NO. 1, 1920. 



