ANNOTATIONS AND ADDITIONS. 75 



that of light almost equally so ; and the existence of nume- 

 rous Infusoria at great depths shews that the polypifers would 

 not want for food. 



In opposition to the hitherto generally received opinion of 

 the entire absence of organic life in the Dead Sea, it is 

 deserving of notice that my friend and fellow labourer, M. 

 Valenciennes, has received through the Marquis Charles de 

 1'Escalopier, and also the French consul Botta, fine specimens 

 of Porites elongata from the Dead Sea. This fact is the 

 more interesting because this species is not found in the 

 Mediterranean, but belongs to the Red Sea, which, accord- 

 ing to Yalenciennes, has but few organic forms in common 

 with the Mediterranean. I have before remarked that in 

 France a sea fish, a species of Pleuronectes, advances far up 

 the rivers into the interior of the country, thus becoming 

 accustomed to gill-respiration in fresh water ; so we find 

 that the coral-animal above spoken of, the Porites elongata 

 of Lamarck, has a not less remarkable flexibility of organi- 

 sation, since it lives in the Dead Sea, which is over-saturated 

 with salt, and in the open ocean near the Seychelle Islands. 

 (See my Asie Centrale, T. ii. p. 517.) 



According to the most recent chemical analyses made by 

 the younger Silliman, the genus Porites, as well as many other 

 cellular polypifers, (Madrepores, Andrseas, and Meandrinas 

 of Ceylon and the Bermudas), contain, besides 92-95 per 

 cent, of carbonate of lime and magnesia, some fluoric and 

 phosphoric acids. (See p. 124-131 of "Structure and 

 Classification of Zoophytes/' by James Dana, Geologist of 

 the United States' Exploring Expedition, under the command 



