878 MOLLUSCA. 



one of these specimens that is represented in the Con. Indica (pi. xv, fig. 4) as 

 H. alcoutongensis, from Pegu. A few specimens were found by Dr. Anderson in the 

 2nd Defile, Irawady; they agree exactly with specimens from Shanghai in the 

 Indian Museum. 



Specimen from 2nd Defile, Irawady : axis 6, diam. 15^ mm. 



Helix (Plectothopis) peeplanata, Nevill. 



Helix (Plectotropis) perplanata, Nevill, I. c, p. 19. 



Only four specimens of this very remarkable form were found at Mimboo, 

 Upper Burma ; a larger series is required to prove with certainty whether it be a 

 distinct form, or only a variety of H. trichotropiSi or of S. tapeina (near var. 

 rotatoria). 



After a most careful examination with a lens, I am unable to trace any sculp- 

 ture whatever on the base ; the seven whorls above are perfectly flat, as in the 

 European JS. explanata ; the keel on the periphery and the shape of the aperture 

 are about the same as in n. trichotropis (especially the Khasi form) ; the umbilicus, 

 however, is considerably more open, quite twice as open as in the Chinese and the 

 above recorded specimens, and about half as open again as in those from the Khasi 

 Hills; the epidermis seems peculiar, having the appearance of being less close in 

 texture and of a decidedly more developed character. 



Axis 4 J, diam. 17^ mm. 



Helix (Plectothopis) oldhami, Bens. 



Helix olcUami, Bens., Ann. and Mag. Nat. Hist., 1859, ser. 3, vol. iii, p. 184; Con. Indica, pi. xv, 



, Helix (Vlectotropis) olclliami, Nevill, I. c, p. 19. 



This species, well represented in the Con. Indica, is next allied to -ST. catostoma 

 and to S. tapeina ; the characters of the aperture distinguish it from the former, 

 the very open umbilicus, &c., from the latter. A single specimen was found at Ava, 

 agreeing exactly with typical specimens from the Arakan Hills. 



Helix (Plectotropis) catostoma, Blanf. 



Helix (TracJiiaJ catostoma, Blanf., Proc. Zool. Soc, 1869, p. 447. 

 Helix catostoma, Blanf., Con. Indica, pi. Ivi, figs 2, 3. 

 Helix (Plectotropis) catostoma, Nevill, I. c, p. 20. 



The specimen figured in the Con. Indica is not taken from a typical Yunnan 

 specimen, but probably from one from Assam. The type in the Indian Museum, 

 found at Ponsee, on the Pirst Expedition, is the only adult specimen from Yunnan. 

 Nine or ten immature specimens were also found, but in none of them are the 



