No. 6 (1921) COMMON MOLLUSCS OF SOUTH INDIA 



179 



fresh-water species, and its presence in quantity in estuarine back- 

 waters, subject during' a considerable portion of the year to brackish 

 water conditions, indicates a marked change in its habits and a 

 re-acquired tolerance for saline conditions. It is used by the same 

 people who eat the common clam and its valves are also employed 

 in lime-burning in Malabar. It is not nearly so abundant as Merc- 

 trix oviii/i ; its habitat is usually further distant from the sea than 

 that of the latter species. 



The shell seldom exceeds 30 mm. in length. 



The Fresh-water Mussel {LaiuclUdcus warginaUs). Although 

 this common Indian species, closely allied to the text-book types 

 so well known to biological students under the names of Anodonta 

 and Unio, is very widely distributed throughout the Presidency, it 

 finds little favour as food. Only in Ganjam have I found it eaten, 

 and then only by the lower castes, being both flavourless and tough. 

 Both in Ganjam and Vizagapatam districts, the valves are used 

 extensively as instruments for peeling mangoes. To prepare one 

 a hole is made in the convex umbonar region by rubbing this part 



of a valve — usually 

 a right one — upon a 

 stonv" till a hole of 

 the right size is 

 formed ; to use the 

 peeler thus formed, 

 it is grasped in the 

 hand with the hol- 

 low side towards 

 the palm, and then 

 one edge of the 

 hole is used to peel 

 off strips of skin. 

 The advantage claimed for this implement over a knife is that the 

 mango does not become stained and its flavour impaired from 

 contract with steel. 



It seems probable that the valve of a fresh-water mussel, having 

 a large hole in the centre, figured in Bruce Foote's "Catalogue of 

 Prehistoric and Protohistoric Antiquities," Madras, 1915, under the 

 number 234-129, from Narsipur-Sangam, Mysore, is a mango 

 scraper of this kind, and not part of a shell necklace as surmised 

 by the author. 



Fig. 45. 



The Fresh- water Mussel {LamelliJetis 

 margiitalis). X f. 



