42. CH1LOMEMSCUS 873 



oculars. Temporals one followed by one. Supralabials 

 seven, third and fourth reaching eye, second, third and fourth 

 high. Inferior labials eight, second smallest, fourth largest, 

 first pair meeting on median line. Genials in two pairs, 

 Posterior much smaller. Scales on body smooth, in 1 3 rows. 

 Anal plate divided. Gastrosteges 121. Urosteges 23, in 

 two series. 



The color above is creamy white, crossed by dark brown 

 bands, most of which are edged with black. These dark 

 markings extend onto the tips of the gastrosteges. They 

 number 32 on the body and seven on the tail. The dark 

 markings on the upper surface of the tail are as distinct as 

 on the body. On the lower surface of the tail very faint 

 continuations of the dark markings complete the rings. The 

 interspaces between the dark bands do not differ much from 

 the dark markings in measurement along the middorsal line. 

 These interspaces are white, each scale marked with a central 

 spot of grayish brown. The posterior portion of the upper 

 surface and sides of the head, including the parietal, the 

 posterior tip of the frontal, the oculars, and most of the 

 supralabials are blackish brown. The lower surfaces are 

 white except where the dark bars involve the tips of the 

 gastrosteges, or appear faintly on the urosteges. 



Length to anus _...! 38 



Length of tail 18 



Remarks. This little snake resembles C. cinctus, but 

 lacks the reddish orange dorsal suffusion seen in that species, 

 and the white cross-bands, instead of being unmarked, have 

 each scale spotted centrally with dark brown. 



Distribution. This species is known from one specimen 

 secured on Isla Partida, Espiritu Santo Island, Gulf of Cali- 

 fornia, Mexico. 



