172 SCIENCE PROGRESS 



Cotylosauria. And it is important to notice that these departures from earlier 

 classifications have stood the test of time, and have not only been maintained 

 and amplified by Prof. Williston himself, but have been adopted by other 

 writers. Points in osteology which were left uncertain in the volume before us 

 have received a definite interpretation in its successor, as exemplified by the 

 determination of the homology of the two coracoidal elements in the shoulder- 

 girdle of Permian reptiles and monotreme mammals. 



It is perhaps hard to decide whether the Permian land-vertebrates of North 

 America or those of South Africa have thrown most light on the relationships 

 between mammals and reptiles on the one hand, and between reptiles and 

 stegocephalian amphibians (and thus with fringe- finned fishes) on the other ; but 

 it is safe to say that each fauna is complementary to the other ; and that 

 without the evidence afforded by the former, that of the latter would be 

 incomplete and in many respects indecisive. A feature common to the South 

 African and North American deposits is the enormous abundance in certain 

 spots of the skeletons and bones of the reptiles ; a notable instance of this 

 occurring in the so-called Cacops bone-bed of Wichita Valley, where in one spot 

 skeletons were found packed like sardines in a tin for a thickness of two feet. 



The value of American Permian vertebrates in helping to solve the puzzle 

 of mammalian descent is incalculable : and of those who have tried to fit a key to 

 the lock, no one has been more successful than Prof. Williston. 



{The late) Richard Lydekker. 



ZOOLOGY 



Behavior : an Introduction to Comparative Psychology. By Prof. J. B. Wat- 

 son. [Pp. xii + 439, with 72 figures.] (New York: Henry Holt & Co., 

 1914.) 



The author of this volume is very firmly convinced that human psychology 

 " has failed to make good its claim as a natural science," and does his best to 

 convince the reader that this is so. This statement will certainly not meet with 

 general acceptance without challenge, but we are not prepared to enter into it 

 here. The author has certainly gone far towards showing that psychology, as a 

 study of behaviour, opens a wide and fascinating field of work for psychologist 

 and biologist alike, and this book will serve a useful purpose if it calls attention 

 to a subject not much studied in this country. 



The aims of the " behaviourist " and the type of problems that he encounters 

 are clearly set out. Considerable space is devoted to the kinds of apparatus 

 used in the experiments, and although this does not make interesting reading it 

 is unquestionably useful if one wishes to repeat or extend the investigations, as 

 are also the short bibliographies given at the end of each chapter. The suc- 

 ceeding part of the book is devoted to studies on instinct, habit formation 

 learning, training, and the activities of the various senses. 



To the biologist the chapter devoted to the origin of instincts is of particular 

 interest, involving as it does a brief inquiry into heredity, inheritance of acquired 

 characters, etc., and the author concludes that since " the activities of organisms 

 must be considered as the functioning of definite structural elements, the problem 

 of the origin of new reflexes, of new instincts, and of new possibilities of habit 

 formation become (sic — becomes) one with the problem of the evolution of morpho- 

 logical characters in general.'' This conclusion is interesting in view of the much 

 discussed question whether function preceded structure in the course of evolution 

 or vice versa, and the author adduces good evidence in support of his view. 



