218 BULLETIN 15 4, UNITED STATES NATIONAL MUSEUM 



A summary of data from the 103 specimens examined follows: 

 Body, 48-92 mm.; tail, 133-243; total lenirth, 181-331; length of tail 

 as percentao-e of total length, 71-77; width of head, 7-15; width of 

 head as percentage of body length, 11.9-17.5 ; hind leg, 32-55 ; length 

 of hind leg as percentage of body length, 55.5-75.5; front leg, 17-32; 

 frontoparietals 1 in all; supraocular granules extending forward to 

 the center of the third supraocular in 98 specimens, and to the pos- 

 terior border of the second supraocular in only 5 specimens. 



It is rather remarkable that 65 of the lizards (63 per cent) had 

 obviously regenerated tails. The general scutellation of this unique 

 form is unusually constant for a species of CnemidopJionis. 



Range. — This lizard is found only on CeraJho Island in the Gulf 

 of California, Mexico (Van Denburgh and Slevin, 19216, p. 396, 

 C.A.S.,M.C.Z.). 



IlaVdat and haViU. — Unfortunately information concerning tlic 

 habitat distribution of ceralhensis is not at present available, and ap- 

 parentl}' nothing is known about its habits. Ceralbo is a high, bar- 

 ren, volcanic island, 16 miles long and only 4 miles wide. Its highest 

 peaks rise to a height of well over 2,000 feet. There are several 

 narrow sand beaches along the shore line, but the main part of the 

 island is very rocky — and it does not seem unreasonable to expect 

 such an environment to produce or preserve a distinct form. It 

 may be of significance that certain colorational details in ceralhensis 

 approach very cloi-ely those of the '' stejnegeH and graluiimi " (so- 

 called) phases of tessellatus^ from the rock3^ mountainous regions of 

 the west coast and from those of western Texas, respectively, and 

 that in no case is the coloration of specimens of fesseUafus from the 

 desert basins definitely approached. 



A-ffiii>ties. — The Ceralbo Island whiptail is related to Tuh'tdus of 

 tlie adjacent mainland, which is apparently its only possible ances- 

 tor. It differs from typical specimens of this supposed parent form 

 only b}^ the presence of a single frontojiarietal plate, the normal 

 presence of three supraoculars, and in the possession of a distinctive 

 coloration. A full account of the relationships of these lizards will 

 be found in the summary of the tesseUatus group (p. 221). 



CNEMmOPHORUS MAXIMUS Cope 

 GIANT WHIPTAIL LIZARD; LARGARTIJA 



1SG3. CncmidopJiortis uuuiinus Cope, Proc. Acad. Xal. .Sci. I'liila., p. 104 (type 

 locality, " Cape St. Lucas, Lower California, Mexico " ; typo specimen. 

 U.S.N.M. No. 5297. John Xantiis, cor.ector) ; Idem. 186(3, p. ;U2; Bull. U. S. 

 Nat. Mus., no. 1, IST.j, p. 4.1. — Lockington, Anier. Nat., vol. 14, ISSO, p. 2!i.j.— 

 Yarrow, Bull. U. S. Nat. Mus., no. 24, 1882, p. 42.— Garman, Bull. Essex Inst., 

 vol. IG, 1884, p. 13.— BouLENGER, Cat. Liz. British Mus., vol. 2, 1885, p. 369.— 

 Cope, Bull. U. S. Nat. Mus., no. 32, 1887, p. 45; Trans. Amer. Philos. Soc, 

 vol. 17, 1892, p. 32.— Van Denburgh, Proc. Calif. Acad. Sci., ser. 2, vol. 5, 



