26 



MADRAS FISHERIES BULLETIN 



VOL. XI, 



a very small pallial sinus it has one well-marked, deep, and angular 

 Average length 44 mm. 



Fresh-water Mussel (Lamellidens marginalis Lamk.). 



Although this common Indian species, identical with the text- 

 book type so well known to biological students under the name 



Fig. II. — Lamellidens marginalis, var. corianus (Lea). 



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

 finds little favour as food. Only low castes care to eat it, but in 

 Ganjam, Tinnevelly and some other districts considerable quanti- 

 ties are consumed when obtainable in abundance. 



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 stone till a hole of the 

 right size is obtained ; to use the peeler thus formed, it is grasped 

 in the hand with the hollow 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 from contact 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 named. 



