ART. 12 REVISION OF LIZARDS OF GENUS CTENOSAURA BAILEY 



39 



the central ones being spinous and equal or nearly so throughout 

 length of tail; lateral spines are much less developed, being in fact 

 smaller than median series and being separated by rows of smaller 

 flat scales; first, second, and third whorls of spiniferous scales sepa- 

 rated by two rows of these small flat scales; third, fourth, fifth, sixth, 

 and seventh by one row of flat scales, and the other whorls of spinif- 

 erous scales by two rows of flat scales; caudal ventral scales smaller 

 than dorsals, three rows corresponding to each pair above, strongly 

 keeled and pointed posteriorly, 



Ifpn^ivrpmpnt^ U.S.N.M, No. 25324, 



Length of head 50 mm. 



Length of body 160 mm. 



Length of tail 265 mm. 



Total length 475 mm. 



Width of head over orbits 26 mm. 



Coloration. — Alcoholic specimen, paratype. Cat. No. 25324, U.S.N.M. 

 Dusky brown showing signs of green with yellow variations on neck, 

 throat, dewlap, and abdomen; dorsal crest and back dark brown 

 with occasional outcroppings of yellow or green. 



Remarks. — This species in possessing a very noticeable dewlap 

 shows a close relationship to Ctenosaura palearis, from Gualan, Guate- 

 mala, and because of this striking peculiarity needs no comparison 

 with other species of the genus. From palearis, however, this species 

 differs in the less marked differentiation of the enlarged tibial scales 

 and in the scutellation of the tail. In baJceri the first, second, and 

 third whorls of spiniferous scales are separated by two rows of 

 smaller flat scales ; the third, fourth, fifth, sixth, and seventh by one 

 row of flat scales, and the others by two rows, whfle in palearis there 

 is only one row of very small flat basal scales throughout. In 

 palearis, the median dorsal crest consists of alternate large and small 

 spines, while in balceri the spines of the crest are equal or nearly so . 

 In palearis the lateral spines on the tail are better developed than 

 are the median series, while in haJceri the scales of the median series 

 are the largest. Then, too, balceri grows to be larger than palearis, 

 even more so than comparative total length measurements mdicate. 

 The head and body of balceri are very much heavier than that of 

 palearis, but the tail is somewhat shorter. 



The dewlap of balceri is not as large as in palearis. This charac- 

 ter, along with the peculiar scutellation of the tail in balceri, tends 

 somewhat to fill the gap between palearis and the other species of 

 the genus. 



Material examined. — 



