142 BULLETIN 17 5, UNITED STATES NATIONAL MUSEUM 



Sacramento Valley, the northern part of the San Joaquin Valley, and 

 the western slope of the Sierra Nevada," the only character he gives 

 to distinguish the form from c. catenifer is the lower average number 

 of dorsal spots. The ranges of variation in the number of spots in 

 the two forms as given by Van Denburgh show a wide overlap, how- 

 ever, and the difference in the averages for the two groups of speci- 

 mens is well within the possible range of geographic variation within 

 a single subspecies and should imdoubtedly be accepted as such. 

 Thus, heermanni must again be considered a synonym of c. catenifer. 

 Diagnosis. — This form may be separated readily from the three 

 forms of the deppei group by the presence of four, rather than two, 

 prefrontals, and the entrance into the eye of a single supralabial on 

 each side, instead of two. From all the subspecies of melanoleucus 

 and the two subspecies of sayi, catenijer may be separated by the 

 shorter rostral, which is never longer than broad, as it is in all the 

 other forms under consideration; catenifer may be distinguished from 

 affinis also by the pattern, since in catenifer the spots vary in number 

 from 58 to 125 (average 87.3), are quadrangular or bar-shaped but 

 never saddle-shaped, and are never reddish in color, and in affinis the 

 spots vary in number from 43 to 86 (average 59.5), and the posterior 

 ones at least are usually saddle-shaped and reddish in color. From 

 vertebralis this form may be distmguished by the lower number of 

 ventrals (206 to 234 in catenifer as opposed to 237 to 262 in vertebralis) 

 and by the coloration. In vertebralis the dorsal spots are black or 

 reddish brown anteriorly, reddish brown in the middle of the body, 

 and black posteriorly and on the tail, and are always more or less 

 saddle-shaped; in catenifer the spots are more or less uniformly brown, 

 grayish brown, or black throughout, and are never saddle-shaped. 

 From deserticola, catenifer may be distinguished by the lower number 

 of ventral scutes. Thus, in catenifer, while the number varies from 

 206 to 234, the number is generally less than 228, the average number 

 being 220; in deserticola, while the number varies from 214 to 259, 

 the number is rarely less than 228, the average being 236. Further- 

 more, in deserticola the light scales of the interspaces between the 

 dorsal spots and of the sides generally bear each a small central black 

 spot, on at least the anterior part of the body, while such spots are 

 generally lacking in catenifer. From annectens, catenifer may be 

 separated by the lower number of ventrals and caudals or the lower 

 number of dorsal spots on body and tail. In annectens the sum of 

 ventrals and caudals is rarely less than 300, and the number of dorsal 

 spots is rarely less than 90, while in catenifer the number of dorsal 

 spots is generally less than 90, and the sum of ventrals and caudals 

 rarely exceeds 300. 



Description. — The body is rather slender and the snout is blunt and 

 almost square. The tail forms 0.122 to 0.185 (average 0.153) of the 



