118 THE ZOOLOGIST. 



NOTICES OP NEW BOOKS. 



The Cambridge Natural History. Vol. VII. Hemichordata, by 

 S. F. Harmer, Sc.D., &c. Ascidians and Amphioxus, by 

 W. A. Herdman, D.Sc, &c. Fishes, by T. W. Bridge, 

 Sc.D., &c, and G. A. Boulenger, F.B.S. Macniillan & 

 Co., Limited. 



This volume is of a more physiological and less descriptive 

 character than some of the preceding publications in this series, 

 and, with the Hemichordata and Ascidians and Amphioxus, this 

 was a necessary expectation that has been well fulfilled. In 

 one hundred and thirty-eight pages Drs. Harmer and Herdman 

 have given a succinct contribution to the knowledge of these 

 more lowly organized creatures, which will be appreciated by any 

 serious student. 



With the Fishes, more general interest will be found, or 

 rather a larger number of zoological readers will be reached, 

 though it is possible that the real knowledge of both groups of 

 animal life does not embrace a larger number of authorities 

 in one than the other, though one is of more popular concern. 

 The account of the Fishes has been divided, Dr. Bridge dealing 

 with the subject exclusive of the Systematic Account of Teleostei, 

 which is undertaken by that well-known and competent authority, 

 Mr. Boulenger. 



Dr. Bridge has mostly treated his subject in a structural and 

 physiological manner, and his section on " Coloration " is very 

 instructive, particularly when he records the many environ- 

 mental changes in the hue of fishes. That in some quarters 

 too great a "protective " character has been ascribed to these 

 changes is probable, especially when the change affects both 

 victim and persecutor alike ; however, in the last case an 

 aggressive value has been predicated, and to-day biological facts 

 without an illuminating theory seem of nothing worth. 



We need scarcely refer to Mr. Boulenger' s contribution ; 

 he is a well-known master of his subject, and we know when 



