40 



CEYLON PEARL OYSTER REPORT. 



oysters (Ostrea sp.), some of very large size. These, as well as a large species 

 of Venus and a mauve Psammobia, are used as food by the natives. The whole lake, 

 measuring more than 20 miles round, is very shallow, most of it being under a fathom 

 in depth. On the southern coast we found there was not enough water to row round 

 near the shore in the ship's boat, so we crossed to near Corrinjahvat in the north 



Fig. 5. Heaps of window-shell oysters (Placuna placenta) on the shores of Lake Tamblegam, from 



the last fishery. 



where great piles of Placuna valves line the shore. We took a few hauls of the 

 dredge here in about 1 fathom of water, and also dredged across the mouth of the 

 inlet known as Narche Coudar (fig. 2, p. 31). In both spots (the whole of Lake 

 Tamblegam may be regarded as Station XXXI.) the bottom was mud with a little 

 sand, and there were few animals : some worm tubes, a few small Medusae, a flat 

 Clypeastroid and some Pagurids in Gastropod shells. 



The bad weather, and a knowledge that the difficulty we should have in getting 

 out would be increased with delay, prevented our spending longer time in Tamblegam 

 Lake, and unfortunately fully as many days as could be spared had now been given 

 to the Trincomalee district. But I arranged with Mr. Horxell that after my 

 departure from Ceylon he should take an early opportunity of visiting Trincomalee 

 and Tamblegam by land, and by making use of native fishermen and divers from the 

 shore, satisfy himself as to any of the matters which we had left undecided. 



The main points on which I wished him to get further evidence were : 



(1.) Whether the water of the harbour differed much in muddiness and salinity 

 at other seasons ; 



