Chap. XL] TKITONIA AKBORESCENS. 



401 



pores, and other polypi, have yet to find a naturalist to 

 undertake their investigation, but in all probability the 

 new species are not very numerous. 



NOTE. 



TEITONIA AEBORESCENS. 



The following is the letter of Dr. Grant, referred to at page 

 385:— 



Sir, — I have perused, with much interest, your remarkable 

 communication received yesterday, respecting the musical 

 sounds which you heard proceeding from under water, on the 

 east coast of Ceylon. I cannot parallel the phenomenon you 

 witnessed at Batticaloa, as produced by marine animals, with 

 anything with which my past experience has made me ac- 

 quainted in marine zoology. Excepting the faint clink of the 

 Tritonia arhorescens, repeated only once every minute or two, 

 and apparently produced by the mouth armed with two dense 

 horny laminse, I am not aware of any sounds produced in the 

 sea by branchiated invertebrata. It is to be regretted that in 

 the memorandum you have not mentioned your observations 

 on the living specimens brought you by the sailors as the 

 animals which produced the sounds. Your authentication of 

 the hitherto unknown fact, would probably lead to the disco- 

 very of the same phenomenon in other common accessible 

 paludinas, and other allied branchiated animals, and to the 

 solution of a problem, which is still to me a mystery, even 

 regarding the tritonia. 



My two living tritonia, contained in a large clear colourless 

 glass cylinder, filled with pure sea water, and placed on the 

 central table of the Wernerian Natural History Society of 

 Edinburgh, around which many members were sitting, con- 



D D 



