408 



SCIENCE 



[N. S. Vol. XXXVI. No. 926 



We fully agree with the author when he 

 states : 



Proportion is a principle in nature which is a 

 purely mathematical one and to be rightly inter- 

 preted by man through the means of geometry; 

 therefore geometry (?) (mathematics) is not only 

 the gateway to science but is also a noble portal 

 opening wide into the realms of art. Still to a 

 great majority of artists, and to the world at 

 large, the effort to relate science with art is now 

 looked upon with the greatest disfavor and even 

 repugnance, and this accounts in a measure for 

 the overwhelming percentage of immature work 

 which characterizes all branches of art in our 

 times. 



It would be another extreme, however, to 

 try to explain all natural forms and every- 

 thing in art by stereotype mathematical laws. 

 This would soon lead to barren formalism and 

 sterility. True art in many of its phases 

 must conform with mathematical, or, more 

 generally, scientific principles. But it can 

 not live without the inspiration derived from 

 physiological and psychological factors. 



Colman's book on " Nature's Harmonic 

 Unity " serves a very noble purpose : a ra- 

 tional appreciation of beautiful natural forms 

 and, based upon it, the cultivation of a truly 

 artistic spirit. 



It is for this reason that, in spite of its de- 

 fects, we wish a large circle of readers for it. 



Arnold Emch 

 University of Illinois 



A Revision of the Amphibia and Pisces of the 

 Permian of North America. By E. C. Case. 

 Washington, Carnegie Institution, Publi- 

 cation No. 146. 1911. Pp. 179, text figs. 

 56, plates 32. 



This monograph is the third of a series by 

 Dr. Case on the Permian vertebrates of North 

 America. The work is divided into five parts : 

 an historical review, a systematic revision, 

 and a morphological revision of the Amphibia, 

 a description of some Permian insects by Dr. 

 E. H. Sellards, and a review of the Permian 

 fishes of North America by Dr. Louis Hus- 

 sakof. The historical review shows the de- 

 velopment of the taxonomy and nomenclature 

 of the Permian vertebrates from the earliest 



descriptions by Cope in 18Y5 to the time of 

 publication. 



In the systematic review the author has been 

 very conservative and has rejected the more 

 recently proposed classifications of the Am- 

 phibia. The one adopted is, in general, that 

 most commonly in use for the Stegocephalia. 

 Under this order two suborders are recognized, 

 the Microsauria and the Temnospondyli. The 

 author has used the term Microsauria (with 

 question) in the sense commonly employed 

 and has made no attempt to define this sadly 

 mixed group. To it are referred the family 

 Diplocaulidffi and genus Diplocaulus. The 

 suborder Temnospondyli is divided into two 

 groups, the rhachitomous and the embolomer- 

 ous. Under the first division are placed 12 

 genera arranged in five families: family, 

 Eryopidse, genera, Hryops, Parioxys, Aniso- 

 dexis (?), and Achelomaj family, Trimero- 

 rhachidas; genera, Trimerorhachis, Tersomius 

 and Zatrachys; family, Dissorhophidse, genera, 

 Dissorhophus, Cacops and Alegeinosaurus; 

 family, Aspidosauridae, genus, Aspidosaurus ; 

 family, Trematopsidse (not Trematosauridse), 

 genus, Trematops (not Trematosaurus) . The 

 embolomerous division is represented by the 

 family Cricotidse and genera Cricotillus and 

 Cricotus. Under the heading, " Incerte 

 sedis," are placed, family, Crossotilidse, genus, 

 Crossotelos; family, Gymnarthridse, genera, 

 Cardiocephalus and Gymnarthrus; all referred 

 to the suborder, Gymnarthria. Under the sec- 

 ond order represented, the Urodela, is placed 

 the family Lysorophidse and genus Lysorophus. 

 In this Dr. Case agrees with the majority in 

 considering Lysorophus an amphibian in 

 opposition to the few that still believe it a rep- 

 tilian form. At the end of this section is a 

 set of tables showing the characteristics of the 

 various families, genera and species. These 

 are so arranged that the related forms can 

 readily be compared. 



In the morphological revision the following 

 genera are treated in detail: Diplocaulus, 

 Eryops, Acheloma, Trimerorhachis, Zatrachys, 

 Dissorophus, Cacops, Gymnarthrus and Lysor- 

 ophus, genera which, till recently at least, 

 were but little known. In an attempt to 

 bring the publication up to date the author 



