THE GENERA AND SUBGENERA OF RACCOONS AND THEIR 



ALLIES. 



By N. HOLLISTER, 

 Assistant Curator, Division of Mammals, United States National Museum. 



The family Procyonidae offers a remarkable instance of a group of 

 mammal genera in which the differentiation in the structure of the 

 teeth throughout the series is nearly uniform in degree from genus 

 to genus, and strictly definite in direction from one extreme to the 

 other. Tliis condition is particularly interesting because of the 

 wide difference between the teeth of genera from the extremes of 

 the line, and because the widely diverse cranial and external charac- 

 ters show no special tendency toward serial grouping. EUminating 

 the very aberrant Bassariscus, which clearly does not belong in this 

 series of genera, the superspecific groups remaining within the 

 Procyonidge, when based chiefly on dental characteristics, fall into 

 as weU-ordered a sequence of steps, connecting the Old- World Ailurus 

 with the American Potos, as it would seem possible to find among 

 living animals. (Plate 39.) 



The one seemingly aberrant cranial feature in Ailurus,^ the presence 

 of the aUsphenoid canal, can not in tliis case be considered a character 

 of family or subfamily importance. The alisphenoid canal in other 

 famiUes of carnivores is known to be absent or present in different 

 genera, in individuals of the same species, or even on the right and 

 left side of the same individual. Of the American groups, Euprocyon 

 is the nearest approach to Ailurus, but if the genera within the 

 family are to be kept of fairly uniform value and degree of differen- 

 tiation, Euprocyon is surely not more than a subgenus of Procyon. 

 The small mountain forms of coati mundis, including Nasua olivacea 

 Gray and its subspecies, differ so greatly from all the other members 

 of the genus Nasua as to require generic separation. They show 

 strong resemblances in several cranial and dental characters to 

 Bassaricyon. 



The cacomistles (Bassariscus), while exliibiting many of the char- 

 acters of the Procj^onidge differ so greatly in the nature of all the 

 teeth that it seems impossible to retain them in the family. The 



> For the loan of a skull o! Ailurus, I am indebted to the Academy of Natural Sciences of Philadelphia, 

 through Dr. Witmer Stone. 



Proceedings U. S. National Museum, Vol. 49— No. 2100. 



143 



