BOOK REVIEWS 2A?. 



sees an animal of their kind. During those times of low numbers 

 of wolves, obviously the young of the caribou and buffalo suffer 

 less from attacks and the herd increases. When wolves are 

 numerous, a corresponding reduction in increase of the herds of 

 caribou follows. This is but a suggestion of the interrelations of 

 life that our ecologists have just begun to study in our native wild 

 regions. 



The book is interesting throughout, its material is presented 

 in an easy-going, conversational style characteristic of the author, 

 and will be found well worth the reading to those who have al- 

 ready learned to fancy Mr. Thompson's style. — O. W. C. 



Animal Secrets Told. A Book of "Whys." Harry Chase 

 Breardley. XII -|- 214 pages. T? half-tone illustrations by 

 Elmer R. Sandborn. Official Photographer, Xew York Zoological 

 Society, and 72 Illustrations from drawings by the Author. 

 Frederick A. Stokes Company. Xew York, 1911. $1.35. 



As the title indicates, the book is a discussion of "Xature's 

 reasons" for structural modifications. The subject matter is dis- 

 cussed in chapters on eyes, noses, ears, mouths, tongues, teeth, 

 bills, feet, tails, coverings and protection. In the chapter on ears, 

 the rabbit's ear. the bloodhound's ear. the elephant's ear. the hip- 

 popotamus's ear. the owl's ear. and the human ear are discussed. 

 Following are some of the conclusions reached as to the reasons 

 for the shape and position of these structures. The rabbit's ears 

 are long so that they will protrude above the grass in which he 

 sits thus making it possible for him to hear in this position. The 

 bloodhound's ears have large flaps which hang down over the ear 

 opening so as to shut out sounds thus making it possible for the 

 dog to concentrate his attention on scent. The elephant's ears are 

 large and fan-like so as to assist in catching sounds after night- 

 fall, and are made to fold back on the neck in order that they 

 may not be torn to ribbons. The hippopotamus's ears are placed 

 on the top of the head so that they will remain above the water 

 when the rest of the animal is submerged. The human ear is not 

 capable of movement because of the fact that man. being a two- 

 legged animal, can rapidly wheel about in any direction thus mak- 

 ing ear movement unnecessary. 



It is seen that the discussions are extremely teleological and 

 that the author has confused reasons for structure with probable 

 structural function. In all the recent research in zoological prob- 

 lems very little light has been thrown on factors affecting struc- 

 tural modifications and it is to be regretted that a book should 



