No. 6 (1921) COMMON MOLLUSCS OF SOUTH INDIA 



119 



behind and completely enfold the shell, protecting it from abrasion. 

 The burrowing habit renders sight valueless, so we find eyes in the 

 Naticas either absent or buried in the integument. 



Ndtica mclnwstomn and the snowy -white A^ mam ilia are two 

 Indian species abundant on sandy shores, where they live upon the 

 burrowing bivalves that abound there. Having found a shell, 

 Natica seizes it and settles down to bore a hole through one of the 

 valves. This it performs neatly and much more quickly than one 

 would think possible. When completed, the long retractile 



Fig II. Life appearance of Natica, the sbell sunk in lobes of the foot. X |. 



proboscis is inserted through the aperture and the flesh of the 

 victim eaten out. They must be very numerous along the Madras 

 coast for their peculiar egg mass, in the form of a broad spiral 

 ribbon (fig. 12), is quite common at times on sand flats and in 

 shallows at the mouths of our rivers (Ennur, the Adyar, Pamban 

 and Tuticorin, for example). The eggs are minute and so mixed 

 and agglutinated together with sand grains that few even suspect 

 these sandy ribbons that look like rolls of coarse sandpaper, 

 to enclose thousands of eggs of a little gastropod. 



Fig. 12. Eg-g ribbon of Natica. (Tuticorin.) X i. 



A less common Indian genus is Sigaretiis. Here the foot is even 

 more greatly developed than in Natica, particularly at the front 



