BY THE REV. J. E. TENISON-WOODS. 1005 



looking through a large collection with every gradation of shape 

 and colour between one species and another, one cannot help being- 

 struck with the slender evidence on which some species rest. One 

 is inclined to say that the species are comparatively few, but the 

 variations are great in extent and endless in number. 



Nevertheless, there are certain peculiar genera which stamp a 

 character on the region, besides certain abnormal species. The 

 fades of the region is Indian. All traces of African influences 

 have disappeared. There is no Achatina, few Pupas, whilst 

 Cyclostoma is beginning to take a subordinate place. Amongst 

 the Cyclophoridfe we find peculiar though wide-spread types ; and 

 amongst the Helicidse unmistakable uniformity. The individuals 

 have all marked characters, so that a small amount of experience 

 suffices to enable us to tell at a glance whether any individual 

 shell is a member of the Malayan fauna. 



There are ift the region we are dealing with about 380 known 

 species or varieties of land-shells divisible into the following 

 genera : — Streptaxis, Ennea, Vitrina, Helicarion, Nanina, Trocho- 

 nanina, Hyalinia, Trochoiniorpha, Fatula, Helix, Cochlostyla, 

 Bulimus, Bulimina, Sienogyra, Rhodina, Glessula, Pupa, Hypse- 

 losloma, Clausilia, Cyclotus, Opisthoporus, Pterocyclos, Spiraculutn, 

 Cyclophorus, Leptopoma, Alycceus, Diplommatina, Opisthostoma, 

 Pupina, Megalomastoma, Ilyhocystis, Georissa. Of these thedominant 

 genera are Nanina, Helix, Cyclophoms, Bulimus, and Clausilia. 

 And this is the case in the Indian fauna. There is in fact the 

 strongest resemblance between the relative proportion of certain 

 genera in the two provinces ; the difference being the complete 

 disappearnce from the Malayan Peninsula of Achatina and some 

 other African genera. The lai'ge predominance of forms of Helix 

 resembles India almost to the very number of species. The peculiar 

 form of Vitrina distinguished as Nayiina, but with slender claims 

 to a generic position, is a feature shared by Ceylon, and to some 

 extent by the Philippine Islands. Nanina is a thin, depressed, 

 umbilicated shell, with a keel at the periphery, highly polished and 

 with a tendency to bi-partite colouring. 



