334 Bihliogra'phical Notice. 



convergence or homoplasy in evolution — one of the puzzles, probably 

 illuminating puzzles, of aetiology — which deserves far more serious 

 study than it has hitherto received. We believe that a careful 

 analysis of the phenomena of convergence would throw much light 

 into many dark corners. We are glad that the author has adopted 

 and firmly adhered to a logical, as well as naturally biological, order 

 of treatment, for even when the reader is not hyperaesthetic in 

 regard to such matters there is an undoubted subconscious effect 

 which gives a peculiar virtue to a well-planned book. 



In addition to its mode of treatment, the book has many out- 

 standing features. Throughout the chapters we find illustrations 

 of the author's intimate knowledge of birds as entire organisms. 

 Mr. Pycraft is certainly one of the " Knowers " to whom Sir Kay 

 Laukester refers in his interesting introduction. Another feature is 

 the fresh independence of many of the author's positions. We 

 have grave doubts about some of them, e. g. the interpretation of 

 the colour of desert-birds (p. 84) ; but there is no doubt that the 

 author advances many that are novel and very suggestive, and none 

 that he has not made his own. Another feature, hard to define, is 

 a robust wholesomeness of outlook, which may be illustrated by the 

 remarks (p. 305) on what was done with "Athene chiaradice." Yet 

 another outstanding feature in the book is the old-fashioned natu- 

 ralist's love that the author has for birds both big and little — a 

 striking feature when one remembers that Mr. Pycraft is an expert 

 osteologist to whom a valley of dry bones is positively delectable, 

 since he can make them live and tell stories. There is something 

 about birds that softens even the hardest morphological heart. 



The book is beautifully illustrated by a series of plates by G. E. 

 Lodge and others, and we wish to emphasize this in regard to them, 

 that they are not only works of art (the photographs, too, of course), 

 but of high scientific interest. We feel that they are there for an 

 intellectual purpose — to illustrate a scientific point — which they 

 effectively serve. As in the case of the simple illustrations scattered 

 throughout the text, they have had brains put into them. The 

 book is pleasant to handle, and the publishers are to be congratu- 

 lated on this first volume of " Animal Life : an Evolutionary 

 Natural History." The people we are sorry for are those who 

 have to write the other volumes, for they have a model set them 

 which will require some working up to ! 



We venture to turn for a little to successive chapters, to illustrate 

 by a few samples the freshness and independence of Mr. Pycraft's 

 work. Thus in the introductory chapter we find a criticism (which 

 demands amplification on the author's part and consideration by 

 other ornithologists) of the use of the preen gland, usually regarded 

 as furnishing an unguent for the feathers. That there are many 

 difficulties in this orthodox interpretation is certain, and Mr. Pycraft 

 makes the suggestion that it may have served or may still serve as 

 a scent-gland. We venture to offer another— that it may be of use 

 as a stimulus to the flow of salivary juice ! The second chapter 

 contains an original restoration of Archceopteryx and a speculation 

 as to the evolution of a wing from a parachute. In the third 



