APPENDIX C. — REPTILES. 355 



temporal region is very much developed and projects over the au- 

 ditory aperture, and is provided along its projecting margin with 

 spines or conical plates, the largest of which is most approximated 

 to the occiput. The eyes seem as if situated in the middle of a 

 groove extending from the snout to the occiput, on account of the 

 projection of the superciliary ridge and temporal region. The 

 lower jaw is generally bordered with a row or two of large plates, 

 which vary in structure and shape according to the species, and 

 furnish good discriminating characters between them. The snout 

 is either truncated or acute. The nostrils are conspicuous, and 

 situated near the extremity of the snout, either within the inner 

 margin of the superciliary ridge, or on its direct prolongation. 

 The upper surface of the head and sides not occupied by the 

 spines or tuberculous knobs, are covered with small polygonal 

 plates, varying in size according to the area over which they extend. 

 The surface of these plates is rugose, wrinkled or keeled, as is also 

 the surface of the spines themselves. They are exceedingly sniall 

 in advance and behind the orbits. The whole surface of the eye- 

 lids is covered with minute scales of a granular appearance ; the 

 margin of the eyelid itself is ornamented with a double row of sub- 

 quadrangular plates, a little larger than the granules of its surface. 

 The lower part of the head from the chin to the breast is covered 

 with small scales, characteristic in each species. The neck is 

 generally very short, appearing as if contracted, the result of 

 which contraction would be the presence of several folds of the 

 skin, concealing the auditory apertures in conjunction with the 

 temporal projection of the head. 



The scales on the upper surface of the body are very irregular 

 in size and shape ; on the neck, above and below, on the pits, 

 along the sides of the back, and on the groins, they assume a gra- 

 nular appearance, while along the middle of the back and on the 

 tail they appear like thin lamellae, very irregular still, and cari- 

 nated or subcarinated. All over the back, sides, tail, and hind 

 legs, there are large, irregularly pyramidal scales, with an acute 

 point and a wrinkled or carinated surface. The margins of the 

 abdomen exhibit one or two horizontal rows of these pyramidal 

 but soft scales, bent backward, extending from the fore legs to 

 the hind ones. The species in which the scales of the back are the 

 largest, is Phr. coronatum, which strikes every one by its rough ap- 

 pearance ; while those in which the scales are the least developed 

 are Phr. platyrhinos and Phr. modestum, whose external appearance 



