PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



by the 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 

 Vol. 91 Washington: 1941 No. 3127 



THE MEXICAN SUBSPECIES OF THE SNAKE CONIO- 

 PHANES FISSIDENS 



By HoBART M. Smith 



In the recent revision of the snakes of the genus Coniophanes Cope, 

 Bailey ^ tentatively concluded that mainland specimens of fissidens 

 must remain under that name, pending the accumulation of further 

 material that would more clearly delimit the geographic races vaguely 

 indicated by material then available. 



Since the appearance of this work many specimens of these reptiles 

 have been collected from critical areas in Mexico, chiefly for the 

 National Museum and for the E. H. Taylor-H. M. Smith collection 

 at the University of Kansas. This new material, combined with that 

 already available, has been sufficient to demonstrate rather clearly the 

 existence in Mexico of four distinct races, occupying as many different 

 geographic and faunal areas and differing from one another in details 

 of pattern as well as in average scale counts. 



I am indebted to Dr. E. H. Taylor and Dyfrig McH. Forbes for 

 much assistance in the field and for the loan of specimens. The study 

 was completed, and a portion of the material was collected, during 

 my tenure of the Walter Rathbone Bacon Traveling Scholarship of 

 the Smithsonian Institution. 



1 Bailey, Joseph, Papers Michigan Acad. Scl., Arts and Lett., vol. 24, pt. 2, pp. 1-48, figs. 

 1-5, pis. 1-3, 19o9. 



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