Cope.] ^kfr [Oct. 16, 



rior labials ; in the nasals being subround instead of triangular ; in having 

 a large instead a small symphyseal plate. The specimen typical of C. 

 orchiopxis has a very low and even imperfect dorsal crest, with a wide in- 

 terruption between the shoulders, while in the other two it is better de- 

 veloped, and in the type of C. nigerrima best of all. 



CTENOSAURA Wiegmann. 



Isis von Oken, 1828, p. 371. Enyaliosaurus Gray. Catal. Lizards, Brit. 

 Mus., 1845, p. 192. 



The species of this genus are restricted to the Mexican and Central 

 American regions as Cyclura is to the West Indian. The species known 

 to me are six in number, as follows : 



I. Caudal whorls complete ; dorsal crest extending only on the an- 



terior dorsal region. 

 Tail round, whorls separated by one row of scales : brown with a few 

 black cross-bands on anterior dorsal region C. hemilopha 



II. Caudal whorls complete ; dorsal crest extending to rump. 

 a Caudal whorls separated by one row of scales. 



Three scales on canthus rostralis ; dorsal crest interrupted at rump ; black 



or dark brown C. laultispinis. 



aa Caudal whorls separated by two or three rows of scales. 



Head short, obtuse ; three scales on canthus rostralis ; dorsal crest inter 

 rupted at rump ; black with yellow cross-bands ; sides of neck yel 

 low , C. brevirostris 



Head wedge shaped ; three or four scales on canthus rostralis ; all, excep 

 the posterior one, deeper than long ; dorsal crest interrupted a 

 rump ; black, with yellow and green cross bands and speckles.. . . 



C. teres 



Four canthal scales, the posterior longer than deep ; head elongate, wedge 

 shaped ; dorsal and caudal crests continuous at rump ; tail com 

 pressed ; green with narrow black cross-bands to belly. . C. completa, 



III. Caudal whorls interrupted ; each represented by a median dor 

 sal spine and two on each side at the base. 



Tail depressed, shorter ; dorsal crest widely interrupted at rump ; pale 



brown with black cross-bands on anterior dorsal region 



C++- guinquecarinata. 



Ctenosaitka hemilopha Cope, Proceedings Philadelphia Academy, 18G3, 



p. 105. Ctenosaura acanthura Bocourt, Miss. Scient. Mexique Kept. 



p. 138. Cyclura acanthura pars, Dum. Bibr., Erp. Gen. iv., p. 224. 



This species is regarded by DeBlainville and Bocourt as the Lacerta 



acanthura of Shaw.* This cannot be correct, as Shaw distinctly states 



that the dorsal crestof his species extends to the rump. It is probably one 



of the species of the next section of the genus (II), but which one I am 



unable to ascertain. 



Lower California only ; Botta ; Xantus. 



• /oology iii. 



