CROrODILTANS, LIZARDS, AND SNAKES. 



239 



Scales oil body veiy small, smaller on the back than on the belly; 

 siiiooth. Dorso-uuchal crest extending' to the sacrum in the male; not 

 beyond the anterior two-thirds of the back in the female; not contin- 

 uous with caudal. Tail depressed at the base, above with alternate rings 

 of large spinose and small smooth scales; only the first four whorls of 

 spines separated from one another by two or three series of smaller 

 scales; the spines on the vertebral line strong and forming a crest, but 



2 ^ 



less developed than those on the sides; scales on lower surface of tail 

 narrow and keeled, each segment, beginning from the seventh, com- 

 posed of only two rings of scales. Five femoral pores. Olive gray or 

 green above, sides, sacral region, and limbs with fine dark-brown net- 

 work; back with darker crossbands, of which a narrow one between 

 the shoulders and two broader ones behind it are black; lower sur- 

 faces whitish ; lower lip with vertical dark-brown bars, throat marbled 



