FISH OF CEYLON. 



131 



the same facility of observation as in my former visit, I was taken 

 to a part of the swamp which had been fished a few days before, 

 and in which, consequently, only one or two very small fishes were 

 taken while I was present. My first visit to Moottoo Eajawelle 

 was paid in April 1862, and was much more satisfactory in its 

 results. 



The swamp of Moottoo Rajawelle is not less, I imagine, than 30 

 square miles in extent; being, as w T ell as one can judge by the eye, 

 fully ten miles long, by three broad. The Negombo Canal runs 

 through it, and must contribute in some degree to keep the water 

 in the swamp at a more nearly uniform level than would otherwise 

 be the case; but, notwithstanding any influence of that kind which 

 may be exercised by the canal, there are, I believe, very considera- 

 ble variations in the height of the water at different seasons. At 

 the time of my first visit, very little water was visible in the swamp, 

 nearly all the surface being covered with rank grass, which had 

 formed a nearly continuous sod over it. Beneath that superficial 

 sod were about two feet of water, or rather of diluted mud, about 

 the consistency of thick Pea Soup, and beneath that again, a solid 

 vegetable deposit very much resembling that which is used as fuel 

 in Ireland under the name of turf. I was at first unable to account 

 for the water being so muddy, as it might be expected that in water, 

 so perfectly still as to have a sod growing over its surface, the 

 earthy particles would soon subside and leave the water clear. The 

 phenomenon is, I believe, to be accoun ted for by the large number 

 of Hoongas and Magooras which inhabit it, which by the perpetual 

 motion of their ribbonlike bodies keep the mud in constant 

 agitation. So perceptible was this effect in the case of some which 

 I had in confinement, that I found it necessary, in order to maintain 

 the clearness of my aquarium, to exclude them from it altogether. 

 The sod, with which the muddy water was covered, was firm 

 enough to support the weight of natives, several of whom were 

 engaged in cutting the long grass for their cattle, while on some of 

 the firmer parts bullocks were to be seen grazing. Thus the 

 singular phenomenon was exhibited of an extensive plain, on the 



