186 BULLETIN 17 5, UNITED STATES NATIONAL MUSEUM 



Original description. — Baird and Girard (1853, p. 72) describe this 

 form as follows: 



Head elongated, elliptical. Vertical plate subpentagonal, elongated, posteri- 

 orly obtuse, with sides concave. Anteorbitals 2; postorbitals 2. Dorsal rows of 

 scales 33, 5 outer rows smooth. Triple series of dorsal blotches confluent for 

 nearly the whole length of the body. 



Differs from P. catenifer in having much smaller dorsal blotches, and more 

 interspaces. The fifteen anterior blotches of the three dorsal series almost united 

 in a transverse or oblique band, anteriorly and posteriorly irregular. The 

 blotches on the flanks are also proportionally smaller than in P. catenifer. From 

 P. Wilkesii, which it resembles in the small size of the blotches, it differs by a more 

 conical head, a narrower and longer vertical plate, and a rostral reaching higher 

 up on the snout. The loral and superior anteorbutal are quite large and the lower 

 anteorbital very small. In one specimen we have noticed 5 postorbitals, the 5th 

 contiguous to the lower anteorbital, thus constituting a continuous chain beneath 

 the eye. Dorsal scales in 33 rows, the 5 outermost perfectly smooth. San Diego, 

 Cal. 243.71.33. 28 5/8.4 13/16. Dr. J. L. Leconte. 



Diagnosis. — From the forms of the deppei group annedens may be 

 separated at a glance by the presence of four, rather than two, pre- 

 frontals, and the entrance into the eye of a single supralabial on either 

 side, instead of one. From the melanoleucus gronp it may be dis- 

 tinguished by the low rostral, which' in annedens is always at least as 

 as broad as long, while in the subspecies of melanoleucus it is at least 

 twice as long as broad. The same character distinguishes annedens 

 from s. sayi and s. affinis, since the former has the rostral nearly twice 

 as long as broad, and the latter has it always slightly longer than 

 broad. In addition, annedens may be distinguished from affinis by 

 the pattern, since in the former the spots are never reddish in color 

 and are rarely less than 90 in number on body and taU, whUe in the 

 latter the spots are generally reddish, at least on the posterior part of 

 the body, and are always less than 90 in number. From vertebralis, 

 annedens may be separated readily by the pattern and coloration. 

 Thus in annedens the spots are never saddle-shaped, are usually black 

 and never reddish, and are rarely less than 90 in number; in vertebralis 

 the spots are always more or less saddle-shaped, are reddish or black 

 anteriorly, reddish in the midregion of the body, and black on the 

 posterior part of the body and on the taU, and are 48 to 81 in number. 



From c. catenijer, annedens may be distinguished by the larger 

 number of ventrals and caudals, and the larger number of spots. 

 Thus in annedens the sum of the ventrals and caudals is generally 

 greater than 300, and the total number of dorsal spots is rarely less 

 than 90, and usually more than 100; in catenifer the sum of ventrals 

 and caudals is rarely greater than 300, and the total number of spots 

 is usually less than 90 and rarely more than 100. The same characters 

 serve to distinguish annedens from deserticola, and in addition the 

 latter frequently has the light scales of the interspaces and sides on 



