208 BULLETIN 15 4, UNITED STATES NATIONAL MUSEUM 



of the tessellatus group. With their linely reticuhited patterns 

 inartyrls ajid canus seem to be decidedly nearer to the coarsely 

 reticulated tessellatus than are the profusely spotted forms, hacatus 

 and catalinsnsis. The spotted pattern evidently develops from the 

 breaking up of fine light reticulations. The northern canus now 

 intergrades with tessellatus, its pattern suggesting derivation by a 

 gradual loss of the longitudinal arrangement in the dorsal markings, 

 and viartyns appears to be merely a melanistic phase of ca7ius, with 

 which it now intergrades in an intermediate locality. 



A further discussion of the relationships of this section will be 

 included in the summary of the tessellatus group (p. 221). 



CNEMIDOPHORUS TESSELLATUS CANUS (Van Denburgh and Slevin) 



WESTERN RETICULATED WHIPTAIL 



lUlil. Cncmidophorus cainis Van Dbnburgh and Slevin, Proc. Calif. Acad. 

 Sci., ser. 4, vol. 11, p. 97 (type locality, " Sal Si Puedes Island, Gulf of Cal- 

 ifornia, Mexico"; type specimen, C.A.S. No. 49153, J. R. Slevin, collector). — 

 Van Denburgh, Occas. Pap. Calif. Acad. Sci., vol. 10, 1922, p. 540. — Schmidt, 

 Bull. Amer. Mus. Nat. Hist., vol. 46, 1922, p. 678. — Stejnegeb and Barbour, 

 Check List N. A. Ainpli. and Kept., ed. 2, 1923, p. 70.— Sclatek, Zool. Eec. for 

 1922, vol. 59, " Reptilia," 1924, p. 23. 



/Systematic notes. — This lizard is being reduced to subspecific rank 

 here because it has been found to intergrade with martyr'is through 

 the population of reticulated whiptails on the geographically inter- 

 mediate South San Lorenzo Island, and thence with tessellatus 

 through the wliiptail on Smith Island. 



Diagnosis. — This form is distinguished solely by its coloration. 

 The back is very finely reticulated and the tessellations sometimes 

 show a tendency to break into spots. Also, occasionally the uni- 

 color condition is approached. This species is separated from typi- 

 cal tessellatus, and hacatus and catalinensis in the same way that 

 those species are separated from tnartyr'is — by the possession of a 

 finely reticulated or unicolor dorsal pattern instead of one with 

 coarse reticulations, lines or spots. It is separated from certain 

 specimens of tessellatus only by having relatively finer dorsal reticu- 

 lations. 



Canus is very close to martyris from which it differs merely in 

 its much lighter ground color. The lower labials of all of the canus 

 specimens examined are light gray, slaty or brown, while those of 

 martyris are deep brown or black. Intermediates between the two 

 forms exist on South San Lorenzo Island, as mentioned above, and 

 these are discussed in detail below under the subject of variation 

 (p. 210). 



Description. — Snout moderately blunt; nostril anterior to nasal 

 suture ; anterior nasal not in contact with second upj^er labial ; supra- 



