304 Alexander G. Ruthven 



tatioii durlug the work, were untiring in tlieir efiforts to assist us 

 in obtaining- results. The generous assistance of tliese men not onl}- 

 added greatly to the data obtained but also made the work verj 

 pleasant for us. I must also acknowledge the assistance of my 

 wife, Floeence Hegle Ruthven, who accompanied me on most of 

 my tramps in the field, eollected a large number of specimens, and 

 did much of the work on the color determinations. 



To Dr. Leonard Stejneger I am greatly indebted for assistance 

 in determining the material of several species. He examined speci- 

 mens of liana austricola, Rana ]}dlmipes, Coleonyx elegans, Anolis hipor- 

 catus, Claudius angustatus and Geomyda imndularia areolata and gave 

 me the results of his study. 



The prints of the photographs and the map were prepared by 

 my assistants, Miss Crystal Thompson and Miss Helen Thompson. 



List of Species. 



In the opinion of the writer no apology need be made for the 

 Space given to the discussion of Variation, habits and habitat distri- 

 bution, in the follovving list. Our knowledge of the Variation and 

 habits of most of the Mexican species is very meager, and contri- 

 butions to these subjects should assist very materially in the deter- 

 mination of the relationships of the forms. 



The color notes were made on fresh material in the held, and 

 the numbers refer to the "Code des Couleurs" by Klincksiek & 

 Vallete. 



Demiophis aiexicanus (Dümeeil et Bibeon). 



Not uncommon at Cuatotolapam. Known locally as the "mano 

 de metate".^) 



The 2 specimens obtained differ from the descriptions of the 

 species in having 185 and 186 folds. The form is stout, the circum- 

 ference being one-sixth to one-seventh of the length. The smaller 

 speciraen measures 350 mm in length and 58 mm in circumference. 

 The color descriptions of this species are quite inaccurate, probably 

 because they have been based upon preserved material. In life the 

 color above is uniformly dark violaceous olive (514). This color, 

 becoming somewhat paler (518), is continued well below the lateral 



1) Fi'om its resemblance in form to the stone roller used by the in- 

 dian women to crush the corn ou the "metate". 



