20 CALIFORNIA ACADEMY OF SCIENCES [Proc. 30 Ser. 



keeled; scales of arm and forearm keeled; lower lateral caudals keeled; 

 dorsals in 14 (sometimes i2>^) longitudinal rows; dark lines along the mid- 

 dles of ventral rows; azygous prefrontal large; interoccipital single; back 

 usually with complete dark cross-bands. 



Type. — Cal. Acad. Sci. No. 4699, San Martin Island, Lower California, 

 Mexico, R. H. Beck, May 3, 1903. 



Description. — Body long and rather slender, with short limbs and very 

 long tail; head pointed with flat top and nearly vertical sides, its temporal 

 regions often greatly swollen in old specimens; rostral plate rounded in 

 upper outline; on top of head behind rostral a pair of small internasals, a 

 pair of small frontonasals, a very large azygous prefrontal, a pair of large 

 prefrontals, a long frontal, a pair of frontoparietals, 2 parietals separated by 

 an interparietal, a pair of occipitals, and an interoccipital; 2 series (of 5 and 3) 

 supraoculars and a series of small superciliaries; temporal scales keeled, 

 lower sometimes only weakly; upper labials much larger than lower; 2 series 

 of large sublabial plates below infralabials, lower larger; gular scales smooth 

 and imbricate; scales on arm and forearm keeled; scales on upper surfaces 

 and sides of neck, body and tail large, rhomboidal, slightly oblique, strongly 

 keeled, strengthened with bony plates, and arranged in both transverse and 

 longitudinal series; number of longitudinal dorsal series 12^^-14; number of 

 transverse series between interoccipital plate and backs of thighs 42-43; a 

 band of granules along each side from large ear-opening to anus, usually 

 hidden by a strong fold; ventral plates about size of dorsals, smooth, imbri- 

 cate and arranged in 12 longitudinal series; number of scales between sym- 

 physeal plate and anus 60-63. 



The ground color above is olive-brown, more grayish on the sides, 

 crossed by from 9-1 1 dark bands. These dark bands may be brown or 

 brownish black, continuous or broken, and are darker laterally, where their 

 scales are tipped with white. Tail proximally marked like back, distally 

 unicolor. Head and limbs unicolor or with traces of olive-brown mottlings. 

 Lower surfaces suffused with gray, edges of scales lighter, darker gray or 

 slate-colored lines along the middle of each longitudinal scale row. 



Length to anus 103 no 117I 



Length of tail 167 128^ 125^ 



Snouttoear 21 25 26 



Width of head 14 19 20 



Head to interoccipital 17 20 21 



Fore limb 27 30 33 



Hind limb 34 38 41 



Base of fifth to end of fourth toe 11 12 13 



The three specimens of GerrJionohis from San Martin 

 Island are very similar to the species now known as G. scinci- 

 cauda, but are much rougher than specimens from central 

 and northern California. Reexamination of the Californian 

 material at hand shows that the San Martin Island form is 

 found throughout the San Diegan Fauna and the western 



1 Type. 2 Reproduced. 



