OCR Text |
Show 864 APPENDIX C.- REPTILES. two posterior angles of the vertex, instead of being acute, as ill Phr. douglasei, are rounded, without any prominent knob or spine. Along the superciliary ridge which overlaps the eyes, the plates are the largest, at least, five of them, there being two very small ones nearly above the middle of the eye. The occipital area exhibits three subcircular plates in its centre, larger than the surrounding ones. A group of large subspinous plates is likewise observed at the base and in advance of the occipital spines. The plates on the snput and along the upper jaw are small and inconspicuous, except the marginal row, on account of an acute projection of each of them. The nose is flattened to excess, slightly concave, and the nostrils are situated at the inside of the superciliary ridge; thus placed in front ( fig. 4). The eyes are circular. The lower jaw wants the first row of large plates which we have seen in Phr. dougla& sii, but the one which exists is so much more developed, than in the latter, and composed of six very conspicuous plates on each side and two small ones ( fig. 2 and 3). Between this row of plates and the margin of the jaw there is an area, covered, on its anterior portion, with two, and, near the angle of the mouth, with three rows of small and polygonal scales* On the lower surface of the head, from the chin to the throat, the scales are small and irregular; on the sides, however, and only for the posterior half of that distance, a row of from five to seven acute- edged scales may be seen. The folds of the neck do not exhibit any thing peculiar under the throat, but, on the sides and behind the ear, they are surmounted with pyramidal and raised scales. The auditory aperture is comparatively small- much smaller than in Phr. douglami. The pyramidal and raised scales of the back are but little prominent. There is but one abdominal series of the latter, as in Ph. douglassii, originating behind the fore legs, but not extending so far backward as in others. The plates in the post- anal groove form two rows, the first composed of six, the second and posterior one of four only. The femoral pores are but few, from six to seven on each side, and quite distant from each other. The head and tail are brown above, the upper part of the body ash- coloured; yellowish and unicolor below. On the sides of the neck is a large patch of black, and two similar ones, but narrow and undulating, on the back. Faint indications of transverse bands of black are observed on the tail. Collected by Captain Stansbury about the Great Salt Lake. |