THE PEARL FISHERY OF 1904. 31 



" kottapakku," which are said to he a small class of oyster but rich in pearls. They 

 ' resemble the oysters of the Chilaw banks, which I know to be 4 years old now, and 

 ' therefore they ought to be fit for fishing in March next. I can find no record of 

 ' this bed having ever been inspected since 1802, and it is a curious coincidence that 

 what was then recorded of its condition might be recorded now on its most probably 

 ' first examination since that time.' " 



The oysters referred to in the above extract were fished the following year, 1879, 

 and the question is at once suggested, " How man}' times between 1802 and 1878, the 

 interval during which this paar received no attention, did oysters mature unknown 

 upon this ground ; and, further, how many other oyster-bearing patches have been 

 left unnoticed for want of more extended inspections?" 



Parasites of the Pearl Oyster. 



" Entozoa were plentiful in the oysters fished this year, both nematode worms and 

 encysted cestode larvae being found : the former especially were more numerous than 

 1 had before seen, and many oysters contained two individuals. A solitary example 

 of the trematode Aspidogaster margaritlferw was found, located as usual in the 

 pericardium. Cestode larvae were particularly abundant in the oysters from the 

 North-west Cheval, and this fact will be referred to when we come to treat of the 

 relative pearl yield of the three sections. 



"More specimens are still needed to enable us to complete our knowledge of the 

 life-history of the pearl-inducing parasite, and till 1 have an opportunity to dissect a 

 number of individuals of the large oyster-eating sting-rays, the Walwadi tirikkai 

 of the Tamils, there can be no hope of filling up this important gap in our 

 investigation. No opportunity offered to obtain one of these rays at the late fishery, 

 my position 12 miles from land precluding access to the fishermen of Pukkulam 

 and Marichchukaddi, the only possible places where I could hope to procure 

 specimens. Several small individuals of Trygon walga were caught by the inspection 

 boatmen. This species does not, however, possess teeth sufficiently powerful to 

 destroy oysters more than a few months old and no parasites belonging to the species 

 found in the pearl oyster were discovered when these fish were dissected. Besides 

 pearl oysters a large number of fishes were dissected in search for the adult stage of 

 the pearl-parasite, and a continuation of such work will form the subject of a detailed 

 report in the future." 



The Yield and Character of Pearls from Different Regions. 



1 hiring the inspection of the Cheval Paar representative samples of mature oysters 

 were collected from the South-west, Mid-west and North-west beds respectively, and 

 from the 7th to the 9th of March Mr. Hornell was engaged superintending the 



