574 Chronicles of Science. [Oct., 



by the absorption tlirongh the external surface of then* bodies of 

 the assimilable organic matter which exists in appreciable quantity 

 in all sea-water, and which is derived from the life and death of 

 marine animals and plants, and in large quantity from the water of 

 tropical rivers. One principal function of this vast sheet of the 

 lowest type of animal life, which probably extends over the whole 

 of the warmer regions of the sea, may probably be to diminish the 

 loss of organic matter by gradual decomposition, and to aid in 

 maintaining in the ocean the " balance of organic nature." 



A translation of Fritz Miiller's interesting study of Crustacean 

 development, which he published under the title ' Fiir Darwin,' 

 has been brought out by Mr. Murray, Mr. Dallas having effi- 

 ciently acted the part of translator. 



The British Hydroid Zoophytes, by the Eev. Thomas Hincks, 

 is one of Mr. Van Voorst's beautiful series, and is worthy of its 

 place in that renowned comj)any. The illustrations are in the 

 form of plates — very copious and very well executed by Mr. Tuffen 

 West. 



