OCR Text |
Show 856 APPENDIX C.- REPTILES. is in great measure destitute of that roughness which is generally associated with the idea of these reptiles. The abdominal scales are subquadrangular or lozenge- shaped, either smooth or slightly keeled, according to the species. On the breast and anterior portion of the shoulders several TOWB of the largeBt scales are seen, very prominent, very acute posteriorly, and strongly carinated or keeled. The anterior and upper portion of the thigh is likewise provided with large scales, but much less conspicuously keeled than on the shoulders. The tail is stout, always depressed at its base: it diminishes very rapidly posterior to the vent, and becomes cylindrical toward its tip. The pyramidal and raised scales are sometimes more conspicuous on its sides and upper surface than on the body itself. The scales below the tail, in the vicinity of the vent, have the general appearance of those of the belly; in the post- anal groove some larger scales may occasionally be seen. Here the scales assume a subvertioillated arrangement. On the conical portion of the tail they are carinated, while they are generally smooth about the vent. The anterior and posterior legs are nearly* of equal size; the latter, however, are slightly stouter. The toes, five in number, are neither short nor very long; the first and fifth are the shortest and either of equal length, or the fifth may be a little longer; the second and fourth somewhat longer than the first and fifth, and likewise either of equal length, or the fourth somewhat longer than the second; the third is always the longest. The scales extend all over the toes, overlapping even the base of the nails: they assume a subtriangular shape, with a very acute posterior summit, and a very distinct carina on their middle. The nails themselves are curved, compressed at the base, and very acute at the tip. On the inferior surface of the hind legs, along the thigh, a series of pores is observed, the femoral pores varying in number and con-fcpicuousness according to the species. The anal pores are totally absent in phrynosomas. We are thoroughly acquainted with six species of the genus JPhrynonomOj viz. Phr. coronatum, Phr. cormtium, Phr. douglaMni, Phr. modestum, Phr. orbiculare, and Phr. platyrhinos. Phr. hatlani is identical with Phr. cornutum; Phr. wieg* manni, with Phr. orbiculare\ and Phr. blainvilki, with Phr. coronatum. After a mature examination of Prof. Holbrook's description of |