1895- SOME NEW BOOKS. 279 



and distinctly brought out, and the book may be confidently 

 recommended as an elementary text-book on the subject to all 

 intending students of chemistry and mineralogy. 



A. R. L. 

 The Evolution of Spots and Stripes. 



Studies in the Evolution of Animals. By Dr. E. Bonavia. Svo. Pp. xiii., 

 362, numerous process blocks. Constable & Co. Price 21s. 



In this volume, which has, we fear, rather a prohibitive price, Dr. 

 Bonavia deals with a variety of subjects, but mainly with the pigmen- 

 tation of mammals. His views upon this much-debated subject are 

 decidedly novel, but not, in our opinion, reliable as probable explana- 

 tions. Nevertheless, the author has shown considerable industry in 

 the collection of his materials, which were gathered, not only in 

 museums and at the Zoological Gardens, but from such apparently 

 unpromising localities as the refreshment room at the Army and 

 Navy Stores. When an author has taken so much trouble in the 

 amassing of fact it is churlish not to allow him a little relaxation in 

 the way of theory. Dr. Bonavia steers a middle course between 

 Eimer on the one hand and Darwin and Wallace on the other ; but 

 his want of success in clearing up the problems is an instance of the 

 fallacy of the reputed safety of middle courses. Like Eimer, Dr. 

 Bonavia holds that utility has had nothing to do with the evolution 

 of the markings upon animals ; if they are useful, it is not much more 

 than a happy accident. He sees in spots the original plan of 

 marking, and holds that stripes have arisen by the flowing together of 

 spots. This is the exact converse of the opinion held by Eimer, who 

 showed some reasons for thinking that a longitudinal striping was the 

 primitive form, which then broke up into spots, and was recombined 

 into transverse stripes. But both authorities are at one in looking 

 upon the self-coloration, as is exhibited, for instance, in the Puma, 

 as the last stage. From this point, however, Bonavia diverges in a 

 direction peculiarly his own, which will not, we think, produce a 

 general conviction in its favour. His view is, in short, that the spots 

 upon carnivorous and other animals are the remains of a former 

 armour-plating, such as is now present in the armadillos. The loss 

 of this hypothetical armour-plating is ascribed by the author to a 

 kind of " lime-famine " produced by too great a demand upon the 

 supplies in the possession of Nature. It follows as an obvious 

 corollary that the Carnivora are the nearest existing relations of the 

 primitive mammalia conclusion which will not, we think, meet with 

 general acceptance. It is true that our knowledge of the earliest 

 Mammalia is lamentably scanty ; they may have possessed an 

 extensive coating of armour-plating, but, on the other hand, the 

 universal opinion is that the existing Monotremata come nearest in 

 structure to the mammals of the Trias and Jura, and that the next 

 nearest are the Marsupialia. Now, neither of these groups has any 

 traces of a Glyptodoii-like skin, and they are not, as a rule, well off in 

 the matter of stripes and spots. The Edentata, which are largely 

 plated, are admitted to be a specialised group, and in any case there 

 is no evidence of their great antiquity. Still, Dr. Bonavia has the 

 courage of his opinions, and argues with great ability in favour of his 

 ingenious suggestions ; and we do not find fault with any man's 

 theories in these days of rapidly-changing views. What we can, 

 without any reservation, congratulate Dr. Bonavia upon are his 

 excellent figures of the skins of various cats. 



F. E. B. 



