PEESENT CONDITION OF THE PEARL BANKS. 43 



shell-tunnelling annelid worms (Polydora), of boring molluscs (Lithodomus), and of 

 encrusting and enveloping sponges. This combination of parasites has induced in the 

 oysters a weakly condition which doubtless predisposes to disease. "As a conse- 

 quence the oysters here are sickly, the rate of mortality is increasing, and compara- 

 tively few ore likely to survive to 1906. Star-fishes are also abundant on this bank 

 and are aiding in the destruction of this bed of oysters." 



On the Periya Paar, where very young oysters are plentiful, small carnivorous 

 gastropod molluscs (Sistrum and other genera) are unusually abundant, and are 

 causing, by boring through the shell, the death of considerable numbers of the young 

 oysters. On the Cheval Paar they are less numerous, and, speaking generally, there 

 is, saving for the great rays, no special or dangerous abundance of oyster enemies 

 upon this the most important bank. 



Valuation Results. 



The exceptionally great number of oysters collected at this inspection was made up 

 as follows : 



40,000 from the South Cheval Paar. 



Mr. Hornell reports that " One-half (20,000) of the South Cheval sample was 

 given to Mr. G. G. Dixon to be treated by his oyster-washing machine for 

 comparison with the other half, which was to be hand-washed and hand-picked in 

 the ordinary manner.* In addition, one bag containing 750 of the South-east Cheval 

 oysters was handed by mistake of the landing boatmen to Mr. Dixon, who will 

 account for it. All the rest of the samples which I collected were washed in the 

 ordinary way by the divers and munducks." 



The result shows that the two highest valuations were yielded respectively by the 

 South Cheval and the South Modragam, the former being worth Ps. 24.65 per 1000 

 oysters, the latter Rs. 17.86^ per 1000. In the case of the former (higher) valuation 

 the result is due to the great weight of pearls present, in the latter to the 

 comparatively high value of the individual pearls. The one gives quantity, due to an 

 unusiial abundance of muscle-pearls, the other quality, owing to fine cyst-pearls being 

 present in a higher ratio than in the former case. 



* See this volume, p. 6. 

 G 2 



