216 BULLETIISr 154, UNITED STATES ISTATIONAL MUSEUM 



evolved from the mainland fes-'ycUatus. Further support of this view 

 is given in the sumniai-y of the tessellatus group (p. 221). 



CNEMIDOPHORUS CERALBENSIS (Van Dcnburgh and Slevin) 



CERALBO ISLAND WHIPTAIL 



1J)21. yvrticariii. ccnilbciixix Tan DENi;ruRGii aiul Si.kvin. Proc. Calif. Acad. Si'i.. 

 ser. 4, vol. 11, p. 396 (type locality, " Ceralbo Island, Gulf of California, 

 Mexico"; type specimen, C.A.S. No. 50510, J. R. Slevin, collector). — ^Van 

 Denbukgh, Occas. Pap. Calif. Acad. Sci., vol. 10, 1922, p. 554. — Schmidt, Bull. 

 Amer. Mus. Nat. Hist., vol. 46, 1922, p. 679. — SxE-jNEOKn and Barbour, Check 

 List N. A. Amph. and Rept., ed. 2, 1923, p. 68.— Sclater, Zool. Rec. for 1922, 

 vol. 59, "Reptilia," 1924, p. 23.— Burt, Proc. Biol. Soc Wash., vol. 42, 1929. 

 pp. 153-154. 



Diagnosis. — This species of Cnemidophorus is closely allied to 

 tcsseUatus and ruhidus, from which it differs chiefly in the possession 

 of only a single frontoparietal plate, and in a decided retardation 

 of the process of tessellation. Even the adults have a more or lens 

 continuous, though irregular-edged, lower lateral stripe on each side. 



Description. — Snout moderately pointed ; nostril anterior to nasal 

 suture; anterior nasal not in contact with second upper labial; su- 

 praoculars 3 ; supraocular granules usually extending forward to the 

 center of the third supraocular; frontoparietal entire; parietals 3; 

 occipitals small; anterior gulars moderate to large, graded, and 

 largest centrally; scales of mesoptychium moderately large, largest 

 centrally; scales of mesoptychium moderately large, largest centrally, 

 in 2-4 transverse rows. 



Bod};' elongate; ventral plates in 8 longitudii!al and 29-34 trans- 

 verse rows; dorsal granules small; limbs w^ell developed; brachials 

 5-6; antebrachials 2-3; brachials more or less continuous with ante- 

 brachials at a point of contact; postantebrachium with a few slightly 

 enlarged granules; femorals o-G; tibials 3-r): femoral pores 13-20; 

 tail elongate, tapering, strongly carinated; caudal plates large, 

 oblique, the keels forming distinct longitudinal lines laterally. 



Coloration distinctive; ventral aspect similar to that of many 

 specimens of tessellatus from the less sandy and more mountainous 

 districts; throat often smoky; under surface of body with many 

 black spots on a whitish or light blue ground color; tail white, yel- 

 lowish or greenish below, but olivaceous and with or without dark 

 reticulations above; femoral spots wdiite, usually numerous; body 

 wdth six distinct stripes, four lateral and two dorsal ; mid-fielcl often 

 3^ellowish upon black, giving but a hazy impression of a seventh 

 stripe, but sometimes wide and blackish ; width of mid-field variable ; 

 other fields usually partly broken by slender, light, transverse bars 

 which extend from the stripes, at least posteriorly; fields blackish 

 and the light transverse bars usually rather finely reticulated, often 

 becoming insensibly lost in the fields. 



