1922] MADRAS PEARL FISHERIES 115 



Such pars are, I fear, uniformly valueless and unworthy of 

 inspection oftener than once in four years. 



Greater attention is required in the southern portion of the 

 division where there exists the possibility, rendered somewhat 

 definite by the presence of the remains of a fishery camp on Nalla- 

 tanni Tivu, of oysters some day maturing. The prospect is not 

 hopeful but is sufficient to justify an inspection in alternate years. 

 The pars requiring the most attention are the Upputanni Tivu, the 

 Nallatanni Tivu and the Vembar Periya Pars. The two first lie four 

 miles off the coast south and south-east of Valinukam Point, the 

 last south-east of Vembar village. 



The rocky bottom on all these pars is the usual brownish dense 

 limestone calcrete, while the sand is in most cases rather finer than 

 that from the Central and Southern divisions and the amount of 

 mud mingled with it is very markedly greater in quantity. 



When inspection of this ground be made, diving and dredging 

 traverses should be made over the whole of the ground at depths 

 between 7% and 10 fathoms to the south and east of the two Tanni 

 Tivu and Vembar Pars. Some of the ground we met here was 

 distinctly promising, and being further from land and at greater 

 depth the bottom is more free from mud than on the inshore banks. 



The characteristic organisms of the Tanni Tivu Pars are 

 sponges in great abundance (see page 83 for names), various 

 Gorgonoids, notably Juncclla juncea, an occasional Astraeid, the 

 tubes of Eunice tubifex and numbers of Pinna; Modiola barbata 

 (suran) generally absent. 



Kumulam Par is valueless, as are also Valinukam and Valinu- 

 kam Tundu Pars and some others in shallow water between 

 Valinukam and Vembar. 



VIII. —THE ANATOMY AND EARLY LIFE-HISTORY 

 OF THE INDIAN PEARL OYSTER. 



The elucidation of the main features in the anatomy of the 

 pearl oyster was the first work I did in the Ceylon pearl fishery 

 investigation as assistant to Prof. Sir W. A. Herdman, F.R.S. The 

 results are given in detail in Volume II of the Ceylon Pearl Fishery 

 Reports published by the Royal Society, 1903-1906, and I propose 

 to give here merely those essential facts that are necessary to the 



