KVXOPSES AND DESCRIPTIONS. 91 



■fifth of total, tapering. Eye moderate, pupil round. Head-shields nine. 

 Frontal narrow anteriorly. Rostral large. Internasals one third smaller 

 than prefrontals. Nasal divided Loreal elongated, angular, horizontal. 

 Orbitals 1 — 3. Posterior 2 — 3. Temporals 14-2. Labials seven, nearly 

 equal, first and last smallest. Infralabials eight (7 — 8), fourth largest. 

 Scales smooth, broad, in 15 rows, outer broader. Ventrals 149. Anal 

 bifid. Subcaudals 39 pairs. 



Body crossed with transverse jet black bars, 25 from head to anus, 

 extending between and involving the exterior rows, becoming narrower 

 on the flanks ; along the back three to four scales long. Space between 

 the bars above orange red, one scale wider than the black bars; on the 

 sides greenish, with the base of the scales blackish. On the tail six black 

 rings, continuing all around, covering two to eight scales; intermediate 

 space red orange, four to five scales wide. Beneath uniform dull green, 

 the black bars of the body not touching the scutellae. (From descr.) 

 Sonora. 



Cc-NTIA OCCIPITALIS. 

 Piiinostoma occipitale Hallowell, 1854, Pr. Ac. N. Sc., PhU., 95. 



"Teeth of equal length, posterior ones not channeled; head depressed, 

 eyes small ; a rostral, two anterior and two posterior frontals ; one anterior 

 and two posterior oculars; a ventical; two occipitals; a small frenal; 

 nostrils in a single plate; seven superior labials, the eye resting on the 

 third and fourth. Abdominals 158; subcaudals 34. 



"Milk white above, with 41 transverse black bands, including seven 

 upon tail and one upon posterior part of head; six complete rings upon 

 tail; throat and abdomen white, with transverse bands continuous with 

 those upon back of tail ; 15 rows of smooth quadrangular scales." Mohave 

 Desert. 



It is possible that this species and C. isozona will yet be united with 

 C. semiannulata. 



var. ANNULATA. 



Completely encircled by black rings. Colorado Desert. 



