XXX INTRODUCTION. 



the older, but certainly from the later beds of that epoch), with 

 Limncea, Vivipara, and others. 



In India tbe Cretaceous rocks of the South Peninsular area 

 are the oldest in which land-shells have been found, and one species 

 was identified by Ferd. Stoliczka as being closely related to the 

 existing Ceylonese genus Gorilla. Further close search in these 

 beds will probably result in the discovery of other species and 

 they would be of extreme interest. 



The Intertrappean beds of Southern India contain several 

 freshwater genera, and a doubtful Pupa is recorded from the 

 Bombay rocks of that age, and land-shells have been obtained in 

 the Lower Intertrappeans referred to AcJiatina; here, again, further 

 search is wanted, minute forms have probably never been looked 

 for. 



Coming down to more recent times, the species of Mollusca 

 which have been found in the Sewalik formation are similar to 

 those now living : only one land-shell, Pupa (Cylindrus) insularis, 

 a species with a range from India to Africa, has hitherto been 

 found; others are freshwater forms belonging to Paludina, Melania, 

 Ampullaria, and Unio. My own experience of the beds in which 

 these fossils occur points to the possibility of much more coming 

 to light when they are worked in the careful manner similar beds 

 have been in this country and in Europe. 



From the later Tertiaries of the Kashmir Valley (Karewah 

 deposits) species of Planorbis and a Helix (?) occur, but those found 

 by me were all flattened by subsequent pressure the beds had 

 undergone : this formation, which is extensive, would reward 

 further search. 



It must be remembered by those w r ho may use this work that 

 the material on which many of the anatomical details here given 

 have been drawn up has been very scanty, and frequently founded 

 on but a single badly preserved specimen, such, for example, as 

 the dried-up animal found within the shell and soaked out ; for in 

 most cases the possibility of obtaining additional specimens from 

 very inaccessible parts of India was remote in the extreme. 



With regard to the conchological side, the descriptions of the 

 genera and species have been drawn up and all measurements 

 taken afresh by Dr. Blanf ord, in most cases from types or from 

 typical specimens. The descriptions of the anatomy have been 

 abridged and the figures taken from those given by Dr. Ferdinand 

 Stoliczka in the * Journal of the Asiatic Society of Bengal,' and 

 those by me in the ' Land and Freshwater Mollusca of India,' and 

 in other papers contributed to various Scientific Societies. The 

 distribution, habits, &c. have been taken from the writings of 

 W. H. Benson, T. Button, F. Stoliczka, H. F. & W. T. Blanford, 

 W. Theobald, G-. Nevill, E. Sykes, O. Collett, &c., or based on 

 the knowledge of a very large number of species collected by 

 myself. 



Though the land-mollusea are not, like birds, butterflies, &c., 

 conspicuous to the ordinary observer, yet they are to be found in 



