Number 139 July 9, 1923 



OCCASIONAL PAPERS OF THE MUSEUM OF 

 ZOOLOGY 



UNIVERSITY OF MICHIGAN 



Ann Arbor, Michigan Published by the University 



A NOTE OX THE GENERA COLUBER AND MASTI- 



COPHIS, AND A DESCRIPTION OF A NEW 



SPECIES OF MASTICOPHIS 



By Arthur I. Ortexburger 



A studv of the new world snakes, commonly called racers or 

 whip snakes, has made it evident that the American species of 

 the genus recently known as Colul)er (L.) form two natural 

 groups sufficiently distinct to he called genera, as will he 

 shown in detail in a forthcoming monograph. Alasticophis 

 and Coluher are the names to he applied to these genera. 

 Since the new form descrihed in this paper must ])e included 

 in the genus ^^lasticophis it is advisal)le to point out the prin- 

 cipal characters of the two genera, which involve differences 

 in the dentition, in the method of reducing the scale rows, 

 and in the structure of the penis. 



Genus AIasticophis 



Diagnosis : Maxillary teeth solid, 16-23 in numl)er. longer 

 and stouter posteriorly, diastema present or ahsent; dentary 



