370 Mr. T. H. Huxley on the Anatomy of the genus Tetliya, 



oceanic movements to regions under the influence of direct, and 

 not of diffused, solar heat; that is, to climates where the sky is 

 clear and the sun always shines, or where it is only transiently 

 obscured by clouds. The White Shark sometimes pays a summer 

 visit to the shores of Europe, confining however its course to 

 where the Gulf-stream extends a warming influence into North- 

 ern seas ; but its appropriate place is in and about the tropics, 

 and within the torrid zone ; and there its sexual and viviparous 

 instincts, and its presence at all times, and in all places, swim- 

 ming in the uppermost waters, make it pre-en.iinently the terror 

 of the deep. Thovigh some veromous Sea Serpents imbue with 

 special dangers the shores of Oxiental seas*, and though fishes 

 are of all animals the most voracious and insatiable, yet as far 

 as man is concerned, if there were no Sharks, there would be no 

 living creature in the Ocean to excite his di'ead or apprehension. 

 Save and except this tribe, all other tenants of the deep, whatever 

 their magnitude or however hostile to one another, are helpless 

 and indefensible against the power of man. 



XXXV. — Zoological Notes and Observations made on board 

 H.M.S. Rattlesnake during the years 1846-50. By Thomas 

 H. Huxley, Assistant Surgeon E..N. 



[Wilh a Plate.] 



II. On the Anatomy of the genus Tethya. 



Thk animal which forms the subject of the present communica- 

 tion was found^ attached to rocks and stones, close to low water 

 mark, upon the shores (skirting one of the smaller bays of Syd- 

 ney harbour) of the beautiful grounds of my friend Mr. W. S. 

 MacLeayf, 



MM. Milne-Edwards and Audouin (Ann. d. Sc. Nat. 1828, 

 tom. XV.) and Dr. Johnston (British Sponges and Lithophytes) 



* In the Transactions of the Zoological Society for 1838 are published 

 Dr. Cantor's observations on Marine Serpents, a group of Ophidians to 

 which but little attention has been hitherto given from the danger of ex- 

 amining them, and from their distribution being entirely tropical. He 

 establishes the circumstance of all the species being highly venomous, and 

 relates the death of an officer in Her Majesty's sei-vice, which occurred near 

 about the time of his writing, within an hour or two after the bite of a Ser- 

 pent caught at sea. Dr. Cantor relates also numerous e-;periments of his 

 own, in which fowls, fish, and other animals, invariably died within a few 

 minutes after the bite had been inflicted. 



t It is not necessary for me to speak of Mr. MacLeay's singular acquire- 

 ments and acum.en ; but I cannot refrain from taking this opportimity of 

 expressing my deep sense of the benefit I have derived from his advice and 

 assistance — always most readily offered. 



