CEYLON NATURAL HISTORY SOCIETY. 151 



wore removed from the water. It was Mr. Mack's conviction that he 

 liad discovered the singing fish. As Dr. Pearson had spent some days 

 in the Batticaloa District in August of last year he was able to criticise 

 Mr. Mack's conclusions. The speaker then went on to describe the 

 conditions of the Batticaloa lake, which was a shallow backwater 

 stretching for many miles to the south of Batticaloa town. The 

 famous singing fish was only heard in a comparatively small area of the 

 lake, between the fort and the entrance to the lake, and the sounds 

 were only heard at night, most favourably at full moon. Sir Emerson 

 Tennent's theory that the sounds were produced by the mollusc 

 Cerithium — a theory which is based upon the traditions of the fisher- 

 men — does not appear to offer a satisfactory explanation. Dr. Pearson 

 was convinced, after investigating the question, that the soixnd was 

 produced by some animal in the water, and not, for example, by 

 frogs on the banks of the lake. That animal may be either a fish 

 or a crustacean. It is well known that both fishes and crustaceans 

 can produce somids. Since Mr. Mack's observations showed that 

 the fish he wrote about only made a noise when removed from the 

 water, the problem does not apj^ear to be any nearer solution. The 

 fact is that many fish when renioved from the water make musical 

 sounds. This may be due to the bubbles of air mixed with the water 

 making a gurgling soimd as the air and water are dra\vn through the 

 gill chamber. Dr. Pearson had noticed this not only in Batticaloa 

 but also in various places along the coast. The fact that the singing 

 fish is only heard in a few scattered localities — ^Batticaloa, Kayts, and 

 Puttalam — and that in each of these localities the distribution of the 

 sounds is extreinely limited, rather disproves the suggestion that the 

 singing fish is a true fish (using the term zoologically), since fishes are 

 generally active swimmers. It is probable that a comparatively 

 sedentary animal, such as a crab, may give rise to the somads which 

 have made Batticaloa so famous. At any rate for the present the 

 problem may be regarded as unsolved. 



The Chairman : Might I ask you how naany noises the fish produced ? 

 Was the sound like sawing ? 



Dr. Peaeson : Quite different sounds. 



The Chairman : Any cadence ; or was it a croaking sound ? 



Dr. Pearson : Quite irregular. It seemed as if each one had its 

 own note. You have about half a dozen sotmds going on at once. 

 Sometimes it was like the croaking of a frog, and sometimes there was 

 a deep note like that of a cello. But none of them were musical. 



Window Pane Oysters in the Colombo Lake. 



Dr. Pearson stated that he had recently received a consignment of 

 shells from Mr. Bakewell, the Assistant Construction Engineer of 

 Railways , who , during operations in the Colombo lake between Captain's 

 gardens and the Royal College, discovered the shells embedded in the 

 mud five feet below the bed of the lake. The shells proved to be of 

 three kinds — Placuna placenta (the window pane oyster). Area sp. , and 

 Tapes rotundata. Since the first discovery Mr. Bakewell has reported 

 the presence of similar shells in other parts of the lake. When Dr. 

 Pearson first received the shells it occurred to him that this was evidence 

 in favour of supposing that at one time the lake was connected with 

 the sea, leaving aside the former connection of the lake with the sea 

 by means of the old Dutch canal. If such connection had existed, 

 the conditions would have been an ideal habitat for the window pane 

 oyster. An examination of the shells, however, proved that, so far 

 as Placuna was concerned, the evidence did not give much strength 

 to such a theory, since the edges of all these shells proved to have 

 been artificially trimmed. It is probable that the shells had been 

 thrown into the lake many years ago. 



