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XXXV. On the Specific Identity of the described Forms of Tanalia. By Henry E. 

 Blanpoed, Esq. Commtmicated by Dr. Joseph Hooker, F.H.S., F.L.S., 8fc. 



Read June 19tli, 1862. 



Any naturalist who has looked through the list of land and fresh-water MoUusca in 

 Sir Emerson Tennent's work on Ceylon can scarcely fail to have been struck with the 

 large number of species there enumerated which are peculiar to the island, especially in 

 the case of such genera as Aulopoma, Ccdcmlus, Tanalia, and Fhilopotamis, the generic 

 range of which is almost equally restricted. The area inhabited by most of these peculiar 

 forms is, indeed, limited to less than half that of the entire island : the plains of the 

 eastern, northern, and north-western provinces possess a fauna in a great measiu'e 

 identical with that of the Central and Southern Carnatic — e. g. Helix vittata, H.falla- 

 ciosa, S. bistrialis, H. Tranqiiebarica (type, and var. semirugata), Bulimns Mavortius, 

 JB. ptmctatus, the wide-ranging B. pullus and B. gracilis, Cyclophorus involvulus, and 

 several freshwater shells ; and the genera above quoted, with numerous peculiar forms 

 of Selix, are restricted, with a few exceptions, to the hUls of the central province and 

 to the undulating, wet, forest-clothed country to the south and south-west. It is true 

 that the apparently endemic character of this fauna may in some cases be rather aj)parent 

 than real, owing to our ignorance of those neighbouring stations the climatal conditions 

 of which most resemble those of South-western Ceylon. The very different physical con- 

 ditions of the northern provinces, on the one hand, and of the hills and south-western 

 parts of the island, on the other, would lead us to expect, a priori, the existence of a 

 distinct and much richer Molluscan fauna in the latter ; and the hills and west coast 

 of the southern extremity of the Indian peninsula, the damp jungles of which present 

 conditions very similar to those of Southern Ceylon, have been too little searched by con- 

 chologists to admit of anything like a fair comparison of the faunas. The little that we 

 do know, however, of the pulmoniferous MoUusca of the Travancore Hills * and of the 

 AnamuUies t indicates an affinity with those of the Nilgiris, which are at least equally 

 well worked out with those of Ceylon, and which include but two species {Bulimus Nilagi- 

 ricus, PfeiflFer, and Achatina Ceylanica, Pfeiffer) hitherto identified as common to the 

 hills of Ceylon, with the exception of such low-country species as range through the 

 intermediate plains and ascend the lower slopes of the hUl-ranges. It seems, therefore, 

 improbable that future discoveries will go very far to diminish the number of forms the 

 range of which is restricted to Southern Ceylon ; and we have before us tlie apparently 



* Benson, Ann. Mag. Nat. Hist. 1861, vol. vii. p. 81. 



f Mr. King's collection of shells from these hills was unfortunately lost on its way to Calcutta. From his commu- 

 nications, however, the above inference is drawn. 



