OCR Text |
Show APPENDIX C.- REPTILES. 847 sented in a state of too great expansion. The head is ovoidal, depressed, subconcave above. The occipital plate is heptagonal, broad, and linear posteriorly, pointed and very acute anteriorly. It is surrounded by twelve smaller plates, six of which, very small, line the posterior edge, while the other six are distributed on the remaining circumference, three to the right and three to the left. There are two vertical plates, the anterior one the largest and pentagonal. In advance of the latter, seven or eight polygonal frontal, plates form a conspicuous group, while near the extremity of the snout the plates are as minute as the scales on the neck. The plates which line the margin of the jaws are small, narrow, elongated, and inconspicuous. On the chin there are three pairs comparatively larger and conspicuous. The scales on the back are spade-shaped and strongly carinated from the neck to the tip of the tail. On the latter region they are a little more acute posteriorly and verticillated. On the sides of the abdomen they are smaller, and their outline less regular. The abdominal scales are smooth, irregularly lozenge- shaped, bidentated posteriorly as in S. scalarid. The opening of the ear is subtriangular, protected by several projecting scales arising from its anterior edge. The toes and nails are very slender; the latter are proportionally long and slightly curved. When the fore legs are stretched backward, the tip of their toes will reach to the knees of the hind ones when the latter are brought forwards. The brilliancy of the general hue having disappeared by immersion in alcohol of the specimens collected, we are not prepared to describe this accurately. As to the markings, they differ somewhat from those of S. scalaris. The row of the large crescent spots along the back is more compact, and not so distinctly bordered with white. The yellowish band that runs from behind the eyes backward to the middle of the tail is much broader; and besides, there is a second similar band extending from below the snout, and passing under the eye and above the auditory aperture, to the insertion of the hind locomotive limbs; the sides, therefore, are not ornamented with vertical, slightly undulating dark stripes; the irregular patches that are seen on that region are entirely deprived of any white margin. The abdomen in the male is blue indigo, as in most species of the same genus. The neck and throat are uni-color in both sexes. This species inhabits the valley of the Great Salt Lake, where it was collected by Captain Stansbury and Lieutenant Gunnison. |