THE PARASITES OF THE PEARL OYSTER. 91) 



where the name Kollae occurs, but when this was compared with W. Baied's 

 copy of Gray's Catalogue, a note in Baied's handwriting was found containing the 

 words Ascaris meleagrina, Kelaart. There seems little doubt that Oeeey miscopied 

 KOLLAR lor Kela \i:t. We have not, however, hern able to find any diagnosis in the 

 reports of KELAART, or any figure of this animal which would enable us to recognize 

 the species, and so it seems that the name is a nomen nudum. 



Three species of Nematoda, representing as many genera, Oxyuris, Ascaris, and 

 Cheiracautliiis, were found in the pearl oysters on this expedition. 



The Oxyuris was met with hut twice, and both specimens were unfortunately lost. 

 They measured barely inch in length. They were found in the intestine of the 

 pearl oyster. The other two species were found encysted in the tissues of the pearl 

 oyster. These were kindly examined for us by Dr. von Ltnstow, who identifies one 

 as new. The specimens which reached England, and which were submitted to him, 

 were both larvae. Dr. von Ltnstow has been good enough to give us the following 

 descriptions : 



Ascaris nieleagrinae, n. sp. Plate III., figs. 42 and 4:!. 



The greatest length is 29 millims., the breadth is 0'55 millim. On the anterior 

 end there are 3 lips, of these the dorsal one is round, with 2 large papillae directed 

 forward ; on the anterior edge a row of small teeth or projections occur, and between 

 the 3 chief lips lie 3 secondary and much less prominent lips. The cuticle is regularly 

 ringed. The oesophagus is g-L- of the total length, and the conically pointed tail 

 is jyg of the same. A pair of anal glands occurs in the end of the alimentary 

 canal. 



Habitat : The larva in the tissues of the pearl oyster Margaritifera vulgaris, 

 Schum., the adult in the intestine of the file fishes Balistes mitis and B. stellatus. 



This Ascarid is usually found within the gonad of the pearl oyster, less frequently 

 within the tissues of the mantle, in all cases in an encysted condition. It appeared, 

 in life, transparent and slightly yellowish to the naked eye. Under the microscope, 

 the intestine is seen to be a brownish -yellow tint. The surface of the body is 

 distinctly and closely annulated. 



In the pearl oyster, its primary host, this Nematode does not attain sexual 

 maturity, remaining encysted and immature so- long as this host lives. The mature 

 stage is reached only after the pearl oyster, happening to be devoured by one of the 

 oyster-eating species of file fishes usually Balistes mitis or B. stellatus suffers 

 digestion within the stomach of the fish. Being thus set free, the Ascarid finds its 

 way into the intestine and attains there eventually a notably larger size than when 

 in its primary host, the pearl oyster. 



Statistics and Details. Out of 24 pearl oysters, 3 to 3^ years old, from the Periya 

 Paar Kerrai, dissected on 7th November, 1902, as many as 10 contained 1 each of this 

 Ascarid. The cysts were lodged chiefly in the gonad in the immediate vicinity of 



O 2 



