CiiAr. IV.j TRITONIA ARBORESCEXS. 481 



explanation of the continuous sounds, and of all source of fallacy 

 from the hum and buzz of living creatures in the air or on the 

 land, or swimming on the waters, I must say that I should be 

 inclined to seek for the source of sounds so audible as those you 

 describe rather among the pulmonated vertebrata, which swarm 

 in the depths of these seas — as fishes, serpents (of which my 

 friend Dr. Cantor has described about twelve species he found in 

 the Bay of Bengal), turtles, palmated birds, pinnipedous and 

 cetaceous mammalia, &c. 



The publication of your memorandum in its present form, 

 though not quite satisfactory, will, I think, be eminently calcu- 

 lated to excite useful inquiry into a neglected and curious part 

 of the economy of nature. 



I remain. Sir, 



Yours most respectfully, 



Robert E. Grant. 



Sir J. Emerson Tennent, d'c. dr. 



VOL. II. 11 



