No. 500] NOTES AND LITERATURE 



557 



this region the groups radiated in all directions, but principally to the 

 northward, and wherever they entered dfferent regions the changed 

 environmental conditions acted as an unfavorable stimulus, which re- 

 tarded growth, and differentiated the groups into dwarfed forms." 



The first forty pages of this notable monograph are devoted to 

 the taxonomy, distinctive features, and "variations" of the 

 garter-snakes; the next one hundred and forty to a detailed 

 account of the various "forms," including description, habits 

 and habitat relations, range, variation and affinities ; then follow- 

 about twenty pages of conclusions and general discussion, a 

 bibliography of about 85 titles, and the index. The eighty-two 

 text illustrations consist of diagrams showing the arrangement 

 of the dorsal scale rows, the head plates, and the arrangement 

 and numerical variation in the labial plates: diagrams illustra- 

 ting the scale formula and its variations in the different forms: 

 distribution as indicated by locality records (plotted on maps) ; 

 and habitat views (half tones). It is altogether an excellent 

 piece of work, which we hope to see emulated in other fields of 

 taxonomic research, for which there is ample opportunity in the 

 higher classes of vertebrates. 



In his introduction Dr. Ruthven alludes to the "barrenness 

 of general results" that has marked the systematic work in 

 herpetology, due in part to the method employed, which has 

 been "largely analytical in its nature, being for the most part 

 descriptive of the existing diversities." While such work is 

 important, it only makes known present conditions; as the 

 author forcibly says, a knowledge of the processes that have 

 brought them about is of the greater interest, since "systematic 

 work can only become a true science when it seeks to formulate 

 the laws involved in the history of the present forms. After 

 analysis, therefore, as has been said, comes the need of a larger 

 synthesis. ' ' 



Dr. Ruthven 's monograph strotiLiiy appeals to the present re- 

 viewer for two reasons : First, when curator of reptiles at the 

 Museum of the Boston Society of Natural History some thirty 

 years ago, he spent much time in trying to unravel the in- 

 tricacies of variation in the garter-snakes, with a view to publi- 

 cation of the results, but other and more pressing interests inter- 

 cepted the work ; secondly, he repeatedly in the early seventies 

 made strong appeals for the synthetic method in systematic 

 work, and has published a large amount of data on individual, 



