48 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 73 



Remarks. — This species along with clarki bridges the gap between 

 quinquecarinata and defensor and justifies the union of the two genera 

 as suggested by Boulenger.^° The chief differences between quinque- 

 carinata, clarTci, erythromelas, and defensor are to be found in the char- 

 acters of the tail. In clarlci and erythromelas the tail, like that of 

 defensor, is shorter than the head and body, one character that sets 

 the three species off from quinquecarinata, whose tail is longer than 

 the head and body. The main distinguishing characters, however, 

 have to do with the arrangement of the spinous scales on the tail. 

 In defensor the entire upper surface of the tail is covered with whorls 

 of strong erect conic spinous scales which are not separated by rows 

 of smaller flat scales; in erythromelas the upper surface of the tail is 

 covered with whorls of very long subequal spines, alternating with 

 a series of small flat basal scales, hardly visible at first glance, but 

 becoming more conspicuous posteriorly until near the middle of the 

 tail, where they become very conspicuous; in clarlci the whorls of 

 spines alternate with whorls of smaller flat scales which are very con- 

 spicuous from the base of the tail to its tip, while in quinquecarinata 

 the tail is covered with alternate whorls of large and smaller scales, 

 the central, and especially the two (occasionally three) lateral series 

 of the former, very large and spinous ; the latter and the three (occa- 

 sionally four) larger series adjacent to the central spinous row flat, 

 except the first two or three whorls of largo scales at the base, which 

 are all spinous. 



Werner described Ctenosaura {Cachryx) annectens from a specimen 

 of erythromelas. Although the specimen is damaged, it agrees in 

 every particular with the true erythromelas, to which it must be 

 assigned. This specimen was collected in 1905 by Phol, but its 

 locality, as I have said, is unknown. 



Material examined. — 



Cachryx defensor Cope, 1866, Proc. Acad. Nat. Sci. Philadelphia, vol. IS, p. 124; 

 1869, Proc. Amer. Philos. Soc, p. 169, pi. 10. — Bocourt, 1870, Miss. Sci. Mex., 

 vol. 3, Reptiles, p. 148, pi. 17, fig. 12, 12a. — Boclenger, 1885, Cat. Lizards 

 Brit. Mus., vol. 2, p. 198.— Cope, 1887, Bull. 32, U. S. Nat. Mus., p. 34.— 

 DuGES, 1897, Soc. Mex. Hist. Nat., ser. 2, vol. 2, No. 12, p. 524.— Berg, 1902, 

 Zool. Garten, vol. 43, No. 3, p. 86-92. 



Ctenosaura defensor Gunther, 1890, Biol. Cent. Amer., Rep. Batr.,p. 58. 



"Boulenger, Proc. Zool. Soc. London, p. 241, 1886. 



