Occasional Papers of the Museum of Zoology 5 



tail; neck ring 2j/ to 3 scales wide, ivory yellow, margined 

 before and behind with black; head above much darker than 

 the general dorsal surface; lower labials, chin shields, and ven- 

 tral scutes prominently spotted with black; caudal plates with 

 black extensions from their postero-lateral corners. Total 

 length, 591 millimeters; tail length, 109 millimeters. Sex, 

 male. 



Diadophis amabilis aiiiabilis ( Baird and Girard) 



1853 Diadophis aniabilis Baird and Girard, Cat. X. Anier. Rept., pt. i. 

 Serpents, p. 113. 



The specimens from San Jose, California, to which the name 

 D. aniabilis was first given were originally regarded as repre- 

 senting a form distinct from the only other then known speci- 

 men of the genus from this state, but later writers have more 

 often regarded these two as the same, and, indeed, have in- 

 cluded under this name all specimens subsecjuently found in 

 the west coast states. That this was an assemblage of several 

 distinct but related races was early evident to the writer, and 

 now, after a study of all the material available, it is evident 

 that not only must the two forms originally described be re- 

 garded as distinct but that, in addition to these, four others 

 must be recognized if we are to attempt an understanding of 

 the genus in this region. 



The subjdivisions of this comi)lex are based largely upon the 

 number of dorsal scale rows, width of neck ring.' maculation 

 of the ventral surface, and the extent of the encroachment of 

 the ventral color upon the dorsal scale rows. 



The name D. aniabilis aniabilis is here restricted to those 

 snakes of the genus inhabiting the San Francisco Bay region 

 and the valleys of the San Joaquin and Sacramento rivers. 

 The characteristics of this race are a narrow neck ring that is- 



