ART. 12 REVISIOlSr OF LIZARDS OF GENUS CTElSrOSAURA BAILEY 45 



backward, alternating with series of smaller yet conspicuous basal 

 flat scales. 



Distribution. — Of the six specimens of this species known to be in 

 museum collections, only one bears a locality label. This one speci- 

 men, M.C.Z. 22454, an adult male, was taken at Ovopeo, Michoacan, 

 Mexico, at an elevation of 1,000 feet, January, 1908, by Dr. H. 

 Gadow, and was received by the M.C.Z. from the British Museum 

 of Natural History in 1926 in exchange. This being the only record 

 for this species I hereby resti'ict the type locality of Ctenosaura darki 

 to Ovopeo, Michoacan, Mexico. 



Description. — M.C.Z. No. 22454, adult male, type; U.S.N.M. No. 

 21499, adult female, paratype. Head normal in length, covered with 

 medium-sized scales, which are slightly rugose and convex. Muzzle 

 slightly decurved, loreal region slightly concave; supra oculars small, 

 being separated from each other by three rows of scales; parietals 

 smaller than those on top of muzzle; nostrils large, on canthus ros- 

 tralis; supralabials 1; sublabials 1; rostral and mental of equal width; 

 ear opening as large or almost as large as orbit; transverse gular 

 fold prominent; dorsal scales small on nape, becoming larger poste- 

 riorly until about the mid-region of the back where they are larger 

 than the ventrals, being rhomboidal in shape, obtusely keeled and 

 slightly carinated, more so in the sacral region. Lateral scales 

 smaller than either dorsals or ventrals. Upper surface of hind limbs 

 with medium-sized spinous scales. Tail slightly shorter than head 

 and body, slightly constricted at insertion, and somewhat depressed, 

 except near distal end, where it is cylindrical; its upper surface with 

 whorls of large subequal spines, directed upward and backward, 

 alternating with series of smaller flat scales which are very conspicu- 

 ous from the beginning; the two larger series of spinous scales adja- 

 cent to the central spinous row smaller than lateral series; lower 

 surface of tail with smaller pointed keeled scales, the number of 

 transverse series not being the same as on the upper surface except 

 on the distal half of the organ. Dorsal crest made up of slightly 

 raised scales beginning just back of head and continuing about two- 

 thirds of the way down the back, gradually merging with the general 

 dorsal scales. Digits shortened. Femoral pores 5-4. 



Measurements. — M.c.z.type, 



No. 22454, male 



Length of head 33 mm. 



Length of body 110 mm. 



Length of tail 132 mm. 



Total length 275 mm. 



Width of head over orbits 20 mm. 



RemarJcs. — In the females the spinous scales of the tail do not show 

 up as conspicuously as in the males, the two series adjacent to the 



