8 MADRAS FISHERIES BULLETIN VOL. XI, 



channel near the Fish-curing Yard at Revu Sonapur village. Here 

 occurs a deposit of large oysters living in great clustered clumps ; 

 in the angles and crevices of these masses the green mussels find 

 suitable lodgment. They vary from single individuals to groups of 

 three or four ; seldom do they exceed this number ; they never form 

 a massive deposit nor do they ever cover their habitat with a living 

 carpet as they do in Malabar. At Sonapur they have economic 

 value but not as food. Owing to certain characteristics of this back- 

 water these mussels are largely infected with the larvae of parasitic 

 worms, and, induced by the irritation thus produced, pearl formation 

 is frequent. For many years past this peculiarity of the Sonapur 

 mussels has persisted and those of the local fishermen who can dive, 

 devote considerable attention to the mussel fishery at times when 

 the water in the channel is low. The pearls found are moderate in 

 size and of poor colour, usually pinkish, but as the mussels yield 

 them fairly abundantly, the beds are well exploited. I saw a few of 

 these mussel pearls when at Sonapur in May 1915, and I was 

 informed that the price paid by the local dealers to the fishermen 

 ranges between Rs. 5 and Rs. lO per tola. 



From the observations made (which I hope to amplify shortly) 

 these pearls are found to have a related origin to that of the pearls 

 sometimes produced in quantity by the common mussel {Mytiliis 

 edulh L.) of France and England. The Sonapur backwater is the 

 haunt of myriads of seagulls and waterfowl and it is from the adult 

 parasites contained in the alimentary canals of these birds that the 

 flat-worm larvae found in the adult mussels are derived. Under 

 certain circumstances occasional larvae induce the formation of 

 pearls in the mantle of the mussel, the dead body of the parasite 

 persisting as the nucleus of the pearl. The life-history of the 

 Sonapur pearl-inducing parasite has yet to be worked out. 



THE Brown Mussel (Mytilus sp.). 



Tamil — Kallikai in South Travancore. 



This mussel is the largest and stoutest species found in South 

 India, attaining commonly a length of 4 inches. It is distinctly 

 larger than the green mussel, but unlike the latter its distribution 

 is limited to a comparatively short length of coast in South 

 Travancore, where it displaces the green species. The coast there 

 is exposed to exceptionally heavy seas during the monsoon, but in 

 spite of this it thrives in great abundance on rocks from low tide 

 level to a depth of about 2^^^ or 3 fathoms. Annually large quantities 



