Septembeb 16, 1910] 



SCIENCE 



383 



SPECIAL ARTICLES 



NOTES ON A LITTLE-KNOWN SPECIES OP SNAKE, 

 OHIONACTIS OCCIPITALIS 



Two specimens of a very rare and peculiar 

 little snake, Cliionactis occipitalis (Hallo- 

 well) were recently presented to the zoolog- 

 ical department of Stanford University. The 

 species is restricted in its distribution to parts 

 of the Mojave and Colorado deserts. Only a 

 few specimens have fallen into the hands of 

 herpetologists and they appear to have been 

 imperfectly preserved and hence not very well 

 described. 



One of the specimens was secured by Mr. F. 

 L. Weed at Calexico, California, February 20, 

 from about a foot beneath the surface in a 

 sand dune. Mr. Weed states that the species 

 occurs in the Imperial Valley wherever there 

 are dunes not far from water, but that speci- 

 mens are only occasionally seen. The other 

 example was received January 21 from an 

 unknown source. The Calexico specimen was 

 in a solution of formalin and somewhat faded. 

 The other had been dead but a short time, the 

 brilliant and striking life colors being per- 

 fectly preserved. The scales of the body 

 were smooth and glistened with a soft polish 

 like fine lacquer. The body was rich creamy 

 white in color, the dorsal surface being 

 slightly tinged with olive, and crossed by 

 numerous bands of an intense brownish black, 

 each space between the bands having a large, 

 oval, transverse spot of bright reddish orange. 

 The head was greenish blue above with a 

 "median reddish orange stripe on the edges of 

 the internasals and prefrontals. When placed 

 in spirits the bright colors rapidly disap- 

 peared, the yellow tint faded from the light 

 areas and the dark bands lost much of their 

 intensity. 



The preserved specimen has a crescentric, 

 black spot on the parietal region of the head, 

 the horns extending forward to the eyes. The 

 spot encroaches on the posterior part of the 

 frontal and occupies a corner of each supra- 

 ocular and the greater part of the parietal 

 plates. There are thirty-one transverse 



blackish bands on the dorsal surface of the 

 body and a terminal spot on the tail. On 

 the ventral surface beneath the tenth band 

 from the head is a black spot, following 

 which in regular succession are similar 

 ones which gradually grow broader until they 

 connect with the dorsal bands forming com- 

 plete annuli. Posteriorly, fourteen bands com- 

 pletely encircle the body, all being more or less 

 constricted laterally. On the dorsal surface 

 the bands average somewhat broader than the 

 space occupied by two scales; ventrally they 

 cover from two to three and one-half gastro- 

 steges, often being very irregular in outline or 

 somewhat broken up into separate blotches. 

 The oval, reddish orange spots, so character- 

 istic of the living example, fade in the preser- 

 vative to deep rose, then pale pink, and at last 

 completely disappear. They are separated on 

 both sides from the black bands by a space 

 equal to the width of one scale, and they 

 extend ventrally to within two scales of the 

 gastrosteges. The Calexico specimen was 

 apparently of the same general color in life. 

 The black areas are less restricted on the body, 

 the fifth band from the head forming a com- 

 plete annulus. There are but twenty-nine 

 spots and bands on the body, the tip of the tail 

 being white. The color notes published by 

 different authors' were evidently based on the 

 evanescent hues of preserved material. 



In superficial anatomical characters the two 

 specimens agree very closely. They measure 

 372 mm. in length, including the tail, which is 

 59 mm. They are rather stocky, cylindrical in 

 shape and very muscular. The head is about 

 as large around as the anterior part of the 

 body, the neck not being perceptibly constricted. 

 The snout is somewhat spatulate, broad when 

 viewed from above, pointed when seen from 

 the side. The rostral plate is very large, 

 twice as wide as high, projecting 1.5 mm. 

 beyond the anterior part of the symphyseal. 



'Cope, Proceedings V. 8. National Museum, 

 1891, p. 605; Boulenger, "Catalogue Snakes 

 British Museum," II., 1894, p. 266; Brown, Pro- 

 ceedings Academy Sciences Philadelphia, 1901, 

 p. 68. 



