ART. 12 REVISION OF LIZARDS OP GENUS CTENOSAURA BAILEY 25 



Cope, 1885, Proc. Amer. Philos. Soc, vol. 22, pp. 379-388. 

 Ctenosaura pectinata Gray , 1845, Cat. Lizards Brit. Mus., pp. 191. — Stjmichrast, 



1880, Bull. Soc. Zool. France, vol. 5, p. 174. 

 Ctenosaura acanthura Boulenger, 1885, (Part) Cat. Lizards Brit. Mus., vol. 2, 



p. 197.— GiJNTHBR, 1890, Biol. Cent. Amer., pp. 56-57, pi. 30. 



Type. — Berlin Museum No. 574, male. 



Type locality. — Restricted to Colima, Colima, Mexico. 



Diagnosis. — This species is very near Ct. hrevirostris, similis and 

 parkeri, having in common with them the dorsal crest extending to the 

 base of the tail, uninterrupted in the sacral region, but differing from 

 each of them in one or more important characters. From hrevirostris 

 it differs in the length of the rostrum or muzzle; the rostrum of hrevi- 

 rostris being short and decurved while in pectinata it is elongate and 

 not decurved in a pronounced manner. The arrangements of the 

 caudal scales in pectinata and hrevirostris are essentially the same; the 

 first five whorls of spinous scales being separated from each other by 

 three rows of small flat scales; the remaining whorls being separated 

 by two rows of small scales for a short distance, then by one row 

 which gradually becomes spinous and similar to the other caudal 

 scales. But in similis only the first and second (and occasionally the 

 third) whorls of spinous scales are separated from each other by 

 three rows of small flat scales, the subsequent whorls of spinous 

 scales being separated by two rows of flat scales up to about the 

 middle of the length of the tail, then by one row of flat scales which 

 gradually become spinous and similar to the other caudal scales just 

 as in the other related species. In parkeri the first seven whorls of 

 spinous scales are separated from each other by four rows of smaller 

 flat scales. 



Distribution. — Ctenosaura pectinata occurs on the west coast of Mex- 

 ico from the State of Nayarit southward to Oaxaca. Collections 

 have been made at San Bias, Maria Madre Islands, and Isabel Island, 

 Nayarit; Colima City, and Mount Colima, Colima; Balsas and 

 Acapulco, Guerrero; and San Geronimo, Oaxaca. 



Description. — Berlin, type. No. 574, adult male; M.C.Z. 2726, adult 

 male and female; 6982, adult female; A.M.N. H. 119, adult female. 

 Head elongate, flat above, covered with small hexagonal scales very 

 distinctly marked off from body. Scales on muzzle smooth and 

 somewhat larger than other head scales; supraoculars small, flat- 

 tened, and hexagonal, externals being only about one-half as large as 

 internals and separated from each other by a row of four scales. 

 Ear opening almost as large as orbit; no dewlap, but a pronounced 

 transverse gular fold present; nostrils large, very near tip of snout, 

 almost tubular, opening obliquely backward; lores flat; supralabials, 



