38 The Ottawa Naturalist. [May 



of one of the most fascinating and certainly one of the most 

 difficult problems in the field of zoology. 



Dr. Patten's paper, "On the Origin of Vertebrates from 

 Arachnids" appeared in 1890; since then he has published many 

 admirable studies in morphology, many of which haye dealt 

 with sections of the larger problem that has occupied his mind 

 for so many years. 



In presenting the arguments in support of his well-known 

 "Arachnid Theory," the author covers a very large morphologic 

 field and offers an immense amount of valuable material, con- 

 cisely and clearly presented. The summary at the close of the 

 chapters is an excellent feature. There are 309 very fine illustra- 

 tions, many diagramatic and all of them instructive. The relega- 

 tion of the "Explanation of the Lettering" to the close of the 

 volume saves much space, but is rather inconvenient to the 

 reader. 



At the close of the last chapter the work of the comparative 

 morphologist is earnestly impressed. 



"Hence, comparative morphology and phylogeny must 

 always constitute the fountain head whence comes our knowledge 

 of creative evolution. Such problems as the phylogeny of 

 vertebrates are, therefore, the most important ones the biologist 

 has to deal with, for on their solution depends our conception 

 of the way in which evolution actually has taken place. 



The cvtologist is too intent on the raw material of life; 

 his field of operation is both too remote and too narrow to give 

 either measurable detail or perspective. To discover the im- 

 mediate causes of any given stage in the evolution of the nervous 

 system or of the endocranium, by a study of chromosomes, or 

 of protoplasm, or by juggling with imaginary hereditary units 

 is as hopeless a task as it would be for the geologist to explain 

 the delta of the Ganges by an appeal to the composition of 

 cosmic matter. 



The naturalist is bewildered by the amazing detail of the 

 finished product, and so much absorbed in the social organization 

 of the present moment, or in the relation of one plant, or animal 

 to the other, and to the environment at large, that he fails to 

 acquire an adequate historic perspective. 



The experimental evolutionist, for a few hours, or months, 

 arbitrarily narrows the environment of an organism and measures 

 the results, if any, with instruments of precision, or with the 

 aid of higher mathematics; but he generally ignores or looks 

 with contempt on the vast experiments already performed for 

 him, where the laboratory is nature, and the results are expressed 

 in species, genera and classes. 



The comparative morphologist aims, not merely to trace 



