286 Proceedings of the Royal Physical Society. 



tentacles, and showing through their parietes white longi- 

 tudinal ridges, which indicate the number of zooid elements 

 of which they are composed. 



In the natural history of this remarkable zoophyte there 

 are other points of peculiar interest, which, haying already 

 described, I need only mention here : the slow development 

 and unique shape of the planuloid . larva ; the powerful 

 muscular structure of the polyps, especially the spiral ones, 

 the office of which last has yet to be discovered ; and the 

 intimate sympathy and combined action which subsist be- 

 tween the various parts of the whole animal. 



III. Notes on Deep Sea Soundings. By E. W. Dubuc,* M.D., R.N. 

 Communicated by Mr James B. Davies. 



The deposits now forming at the bottom of the ocean 

 possess a peculiar interest from a zoological as well as from 

 a geological point of view, especially when we consider the 

 importance of the natural processes upon which they are 

 capable of throwing light. 



It is only of late years, however, that we have been en- 

 abled with any degree of accuracy to sound the vast depths 

 of the ocean, to map out the varying configuration of the 

 solid substrata, and to examine into the nature of the latter. 

 We owe this in great measure to the invention of an im- 

 proved form of sounding apparatus by Mr Brooke of the 

 United States Navy. 



Specimens thus obtained from great depths were sent to 

 Professor Ehrenberg of Berlin, and Professor Bailey of New 

 York. The latter submitted samples of the sea bottom from 

 that part of the North Atlantic which covers the telegraph 

 plateau to microscopical examination, and found them to be 

 filled with minute organisms, and to contain neither sand 

 nor gravel. The organisms were mainly calcareous, consist- 

 ing of the shells of various genera of Foraminifera {Poly- 

 tlialamia of Ehrenberg). There were besides a small number 

 of the siliceous shields of diatoms. 



* I observe, with much regret, a notice of the death of Dr Dubuc on board 

 H.M.S. Cossack, at the Cape of Good Hope, on the 10th of January 18G2, at 

 the early age of 24. — J. B. D. 



