DESCRIPTION OF THE PEARL-OYSTER BANKS OF THE GULF OF MANAAR. 119 



greatly predominating. Only a few pearl oysters were found, on the small patches of 

 rock, when we examined the ground. 



The sand here is a coarse, yellow quartz sand, and the " rock " is a coarse, calcareous 

 sandstone or calcrete the large quartz grains, up to an inch in length, heing 

 apparently embedded in a matrix of carbonate of lime. There are dark, ochreous 

 patches in places. Out of 187 dives, 140 were on sand and 47 on rock. 



Scarcely any living Coral was seen, and no Algse ; amongst the commoner animals 

 were : Branched Gorgonids and Hydroids, Terebellids (many, large), Area sp., 

 Avicula radiata (on Gorgonids), and Leptoclinum sp. 



OOLAWITTI PAAR. 



This lies about 8 miles north of Negombo, at a depth of 7|- to 8|- fathoms. On the 

 bottom coarse, yellow quartz sand predominates; but there is "rock" in patches, 

 and there some small (6 months) pearl oysters were found. 



The " rock " is consolidated sand, of a dark brown colour, as if iron were present in 

 the cementing material. Mr. Lomas describes it as a " reddish-brown calcrete with 

 the sand rather loosely united." 



On these masses, and penetrating them, are found upright, branched, tough leathery 

 tubes in abundance. Professor M'Lntosh, in the "Challenger" Report on the 

 Polychaeta, figures a similar tube from the Gulf of Manaar, and states his belief that 

 it will prove to be the home of a Eunicid. Mr. Hornell has been able to establish 

 the correctness of this suggestion, as he has removed two fine Eunicids* from these 

 tubes. 



Negombo Paar. 



This lies off Negombo, about 3 miles off-shore, at a depth of 8 to 9 fathoms. The 

 bottom is sand and patches of "rock" (reddish-brown blocks of calcrete), exactly 

 similar to that of the Oolawitti Paar. The oysters present when we examined the 

 paar were probably from 2 to 6 months old, and were mostly attached to the rock, 

 some in clusters on the sand. They were in considerable abundance. 



There is another small paar, south of Negombo, which was found by Captain 

 Donnan in 1901. It is similar in character to the Oolawitti Paar. Neither of these 

 Negombo Paars, however, corresponds to the spot off Negombo where we dredged up 

 young pearl oysters from the " Lady Havelock " in February, 1902. Mr. Hornell, who 

 has been examining the early charts, is of opinion that the " Lady Havelock " paar 

 is the original Oolawitti Paar. That does not matter much. What is of real 

 importance, is to recognise that there are a number of small, more or less hard areas 

 in the shifting sand, on which from time to time " strikes " of young oysters may 

 make their appearance, and may possibly grow to maturity, but more usually become 

 thinned out by their natural enemies or overwhelmed by sand. These small paars 

 * To be described in Mr. Hornell's Report on the Polychieta, in a later Part. 



