65 



LIST OF THE SPECIES OF GATAULUS FOUND IN CEYLON, 

 WITH DESCRIPTIONS OF SOME NEW LAND-SHELLS FIIOM 

 THAT ISLAND. 



By E. R. Sykes, B.A., F.Z.S., etc. 



Read llth Febriiartj, 1898. 



PLATE V. 



Since my former paper was read a year ago,' a considerable amount 

 of additional material has passed through, my hands. In the process 

 of identification, two or three points referring to the validity of species 

 have occurred, that it will be well to deal with first. 



Pfeilfer in 1853 described^ Helix Thivaitesi, and Reeve gave a 

 figure of it,^ drawn from an example in the original type series ; 

 Dr. Jousseaume in 1894* described Microcystis suavis from Nuwara- 

 Eliya, and renamed Reeve's figure as If. Nuwara, stating that it was 

 not the same as Pfeiflter's species, and that both occurred at Nuwara- 

 Eliya. I have examined specimens said to have been identified as 

 M. Thwaitesi and M. suavis by Dr. Jousseaume, and also Pfeiffer's 

 types, and come to the following conclusion : that Dr. Jousseaume' s 

 M. Thwaitesi is not that species, but is my Macrochlamys circumsculpta, 

 while his M. Nutoara is really M. Thwaitesi, as is also his M. suavis. 

 This latter appears to be a variety with the spire a little more 

 depressed, the umbilicus a trifle larger, and the mouth slightly 

 different in shape ; it may be of varietal, certainly not of specific rank. 



I cannot trace sufficient distinction between Helix histrialis, Beck, 

 H. Ceylanica, Pfr., and H. Taprobanensis, of Dohrn, to warrant in my 

 opinion their separation as independent species ; they appear to be all 

 forms of one species, varying somewhat in size, shape, and banding. 

 Colonel Godwin-Austen, from anatomical considerations, has recently 

 placed them in his genus Nilgiria.^ 



Helix verruc'ula was described by Pfeiffer® from Cuming's collection ; 

 recently Dr. Jousseaume has renamed the figure given by Hanley and 

 Theobald " as Nigritella nerva : inasmuch as they state in the explana- 

 tion of plates that "Cuming's type, now in the British Museum, is 

 here represented," the new name seems an unnecessary expenditure 

 of ink. The reference to the Proc. Zool. Soc. given by Dr. Jousseaume 

 refers to H. hyphasma, not the present species. 



' Proc. Malac. Soc, vol. ii, pp. 233-7, pi. xvi. 



2 Proc. Zool. Soc, 1853, p. 125. 



3 Conch. Icon., sp. 1,336. 



* Mem. Soc. Zool. France, vii, p. 10, pi. iv, fig. 

 ® Land and Fresh-water Moll. India, vol. ii, p. f 

 ^ Proc. Zool. Soc, 1854, p. 60. 

 '' Couch. Ind., pi. cl, fig. 9. 



