LAND & FRESH-WATER SHELLS COLLECTED IN BOMBAY. 133 



The animal is nearly always of the same yellowish colour, and it would 

 be interesting to know what is the cause of the variation in the shell ; 

 dark specimens seem to abound in some localities and light ones in others. 



The animal has the mucous pore on its tail plainly defined, but it 

 is not surmounted by any protuberance, neither does any part of the 

 mantle overlap the shell at the aperture to form what are known as 

 shell-polishing lobes. 



The absence of these characters is distinctive of the genus Ariophanta. 



Ariophanta bajadera (Pfeiffer) is also a sinistral shell., not quite as 

 large as A. Icevipes, but deeper and more globular, also much more 

 fragile, of a greenish-yellow colour. The shell is beautifully corru- 

 gated radially, and the last whorl is large in proportion to the others. 



The animal is somewhat similar to A. Icevipes. 



The shell being very thin and transparent, some of the anatomy of 

 the animal can easily be discerned through it, including the kidney 

 and the pulsating heart. 



This species does not appear common in Bombay, but is fairly 

 plentiful at Matheran, where it seems to grow a stronger shell. 



Nanina pedina (Benson) is quite our commonest garden snail ; the 

 shell is dextral, rather larger and more fragile than that of A. Icevipes, 

 being about 1|" across and of a brownish colour. It is more or 

 less flattened in shape, but different individuals vary a little in the 

 raising of the spire. The umbilicus is small. 



The animal has a prominent horn-shaped protuberance on its 

 mucous pore, and two shell-polishing lobes to its mantle almost like 

 feelers in shape, one doubled back on the centre of the whorl, the 

 other pointing forwards in prolongation of the suture. The animal at 

 times, when disturbed, secretes mucous very profusely, for exactly 

 what purpose it is hard to say; it maybe some protection from the 

 attacks of insects — ants for instance. The heart can also be observed 

 pulsating in this species. I have reason for suspecting this snail of 

 cannibal propensities. 



This species is exceedingly common at Matheran. 



Nanina {Microcystina) tenuicola (Adams) is a very much smaller 

 species than the foregoing, the shell being only from £" to §" across 

 thin and transparent, of a greenish-yellow colour, dextral in shape, 

 the spire a good deal raised. The animal has no shell-polishing lobes, 



