374 DR. H. GADOW ON EVOLUTION [Mar. 20, 



Cnemidophorus labialis Stejneger. 



Based upon five specimens from Ceclros Island, Lower California. 



Distinguished from all the other Cnemidopho7-i by the nasal being 

 n contact with the second upper labial, which latter completely 

 separates the postnasal from the first labial. Supraoculars 4, but 

 in the figure given by Cope the 4th or posterior supraocular is 

 broken up into two or three smaller scales ; a condition Avhich may 

 be an individual abnormality, but which also is shown in the figures 

 of C. sericeus and semifasciatus. The collar, to judge from the 

 figure, is composed of decidedly small scales, only those of the 

 middle being somewhat larger ; all the scales, however, form the 

 posterior shai-p margin of the collar, there being no granules. 

 The posterior surface of the forearm is covered with granules, 

 about three i-ows of which are slightly enlarged. Femoral rows 5, 

 or only 4. Pores 12 to 13. Only two large preanal plates, the 

 usual posterior pair being fused into one broad plate. Total 

 length 55 mm. 



" Colour above dark brown, with six longitudinal light lines 

 and a median clay-coloured band of the same shade as the top of 

 the head ; two light longitudinal lines on fore limbs and three on 

 hind limbs ; under side whitish, more or less suffused with bluish, 

 especially on the flanks." 



This little species is veiy puzzling. The arrangement of the 

 labials and nasals is unique. The condition of the collar is 

 essentially that of the tessellcdus-gvo\v^, but recalling the gularis- 

 group by the sharp edge without granules. However, a very 

 similar collar is given to C, octolineatus and C. inorncdus in Cope's 

 figures. The slightly enlarged granules on the forearm point to 

 C. deppei and to C. sexlineatus, which latter is, moreover, closely 

 approached by the colour-pattern. The three peculiar pale stripes 

 on the hind limb recall the equally peculiar three black stripes of 

 C. martyris. 



References to the origincd descriptions of species 

 of Cnemidophorus. 



C. sexlineatus Linne, Syst. Kat. xii. 1766, p. 364. 



DeppeI'Qvow^. 



C. guttatios Wiegm, Herpetolog. Mexicana, 1834, p. 29. 



=:microlepidopus Cope, Proc. Am. Phil. Soc. xvii. 1877, 

 p. 93. 



= unicolor Cope, ibid. 

 C. deppei Wiegm. Herp. Mexic. 1834, p. 28. 



= decemlineatus Hallowell, Proc. Ac. Philad. 1860, p. 482. 



= li7ieatissi')nus Cope, Proc. Am. Phil. Soc. 1877, p. 94. 



= alfaronis Cope, Proc. Ac. Philad. 1894, p. 199. 

 C immutahilis Cope, Proc. Am. Phil. Soc. 1877, p. 93. 



= C. guttattos var, striata Gadow, Proc. Roy. Soc. 1903, 

 p. 155. 



