Ko. 6 (1921) COMMON MOLLUSCS OF SOUTH INDIA 



157 



of the handsome green colouration of the horny membrane or 

 periostracum investing the exterior surface of its valves ; the 



other is an even 

 larger species, less 

 elegant in contour, 

 coated with a coarse 

 brown periostracum 

 that looks com- 

 monplace when con- 

 trasted with the 

 vivid tint of the 

 green. The green 

 species is distri- 

 buted widely upon 

 the Madras coasts, 



liG. 38. The Green Mussel {Mytilus viridis). X 



extending as it does 



almost continuously 

 from South Kanara on the West Coast to the borders of Orissa 

 on the East. The brown form, on the other hand, is confined so 

 far as I am aware, to the extreme south of Travancore and of the 

 Tinnevelly district. 



No representatives of the closely related genus Modiola are 

 eaten, although several species are found, particularly in Palk 

 Bay, where the sea-bottom is frequently carpeted over hundreds 

 of acres with vast multitudes of Modiola barhata, Modiola japouica and 

 allied forms. These seldom grow more than an inch in length and 

 live generally at a depth of 3 to 5 fathoms, hence their non-utiliza- 

 tion as food. Could they be cheaply collected in quantity, they 

 would form both an excellent food and, when dried and pul- 

 verized, a first-class manure. 



Throughout South Malabar the green mussel is usually termed 

 kaduka which appears to be a corruption of kadalkai (sea-fruit) 

 by which name it is known amongst better educated people ; in 

 Cochin this same shell-fish is known as nilakakka, the " long 

 kakka " in contradistinction to the ordinary kakka which is the 

 common backwater clam {Meretrix casta ovum). In Kanarese it is 

 pacile, in Tulu, ageer, and in Tamil kallikai in the south, pachchai- 

 ali at Pulicat. 



Mytilus viridis, although so widely distributed, is found in 

 large quantity only on the West Coast from South Kanara to the 



