PROCTOTRETUS. 327 



No gular fold. No femoral pores ; preanal pores in the male sex. 

 Tail tapering, simple. Fingers and toes five, simple. 



SYN. Proctotretus, BUM. & BIBR. Erpet. gen. IV, 1837, 266. BELL, Zool. Voy. 

 Beagle, V, 1843, 1. FITZ. Sjst.Kept. 1843, 74. GRAY, Catal. Lizz. Brit. Mas. 1845, 

 216. GUICH. in Gay, Hist, de Chile, Zool. II, 1848, 23. GRD. in Gllliss U. S. N. 

 Astr. Exped. S. Hemisph. II, 1855, 217. 



OBSERV. This group is characterized by the presence of preanal 

 pores in the male sex, and in the total absence of femoral pores. The 

 body is rounded off, somewhat depressed, covered with imbricated 

 scales, varying considerably in size and shape : the dorsal ones, and 

 often the lateral also, are carinated : the keels being more or less deve- 

 loped, either projecting beyond the posterior edge of the scale, which 

 is then acuminated or lanceolated, else not extending quite to the 

 margin of the same, which, in that case, is rounded or subrhomboid. 

 The lateral scales being either equal to the dorsal ones, subequal, or 

 smaller. The abdominal scales are larger than the lateral ones, gene- 

 rally smooth, rounded, and entire posteriorly, sometimes acuminated, 

 subciliated, or emarginated. The dorsal region is generally even or 

 without crest : in a few instances, pectinated ridges may be observed. 



The head, which is more or less depressed, is subquadrangulo-pyra- 

 midal, narrow, rounded, or subtruncated anteriorly. The cephalic 

 plates are of small, or of moderate size, polygonal or lanceolated, either 

 imbricated and carinated, else unimbricated and smooth. There are 

 teeth, more or less conspicuous, on the palatine or pterygoid bones. 

 The temporal scales are smooth or carinated, imbricated or not. The 

 auricular aperture is either denticulated, tubercular, or granular in 

 front, else simple : the tympanum being situated somewhat below the 

 surface of its orifice. The sides of the neck are either even, without 

 fold of any kind, or an indistinct longitudinal one is observed ; some- 

 times, a vertico-oblique, scapular fold is observed with an indistinct 

 longitudinal one ; at others, it is multifolded or rumpled. Scales simi- 

 lar in shape and structure to those of the back or sides, may extend 

 over its surface or folds, or the latter may be entirely granular. There 

 is no gular fold or collar. 



The body is supported by four limbs, terminated by five fingers and 

 five toes, simple and clawed; their upper surface is covered with scales 

 similar in shape and structure to those protecting the body. The in- 

 ferior aspect of the arms and posterior aspect of the thighs, are either 



