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Show 24 ZOOLOGY OF TilE VOYAGE OF TilE BEAGLE. GENUs-LEIOCEPHALUS. Gray. LEIOCEPHALUS GRAYII. PLATE XIII.-FIG. J • C1·istd d{J7·sali elevata; cauda sub-compressd; squamis ventmlibus 1·/wmboideis, lcevibus; margine anteriore meatus auditorii quadridentato; squama occipitali magna. Habitat, Galapagos Archipelago. DESCRIPTION.-IIead, viewed from above, forming a nearly equilateral triangle, covered with irregular slightly raised scales. Supra-orbital ridge prominent, and covered with a series of elongated and imbricated scales. Occipital plate large, pentagonal, notched at its posterior margin. The anterior margin of the auditory passage is strongly quadridentate, from the existence of four long and rather narrow scales. Scales of the temple obtusely carinated, not imbricated; those of the back strongly and acutely carinated and disposed in numerous rows, converging backwards towards the dorsal crest. V cntral scales rhomboidal, not carinated. Dorsal crest elevated, composed of flat vertical scales, so closely placed as to constitute an almost continuous line, extending from the neck to the end of the tail. Tail somewhat compressed at the base, becoming nearly round towards the middle. Scales beneath the feet and toes carinated. CoLoun.-The colour of this species is thus stated in Mr. Darwin's notes:-" Upper part clove brown, passing into black brown with black spots. Sides slightly tinted with orange ; some of the scales of the crest near the head are white; belly nearly white; the whole of the throat before the fore legs glossy black. This is the most common variety in the Archipelago. The black spots are not unfrequently placed in waved t~;ansverse bars, and are sometimes arranged longitudinally. DIMENSIONS. Length of the head ....................... . of the body ......... .. ........ .... . of the tail ....................... . Total length ...... Inches. Lines. 0 5 9 8 5 Of this species, one of the most beautiful in the whole order of Saurians, Mr. Darwin obtained numerous specimens, one only of which is fully adult. In the younger individuals the dorsal crest is low and almost inconspicuous. It differs very materially from either of the two species previously described, and I have dedicated it to Mr. Gray, who first distinguished the genus. Mons. Bibron, unaware that Mr. Gray had already constituted the genus under the name Leiocepltaltts, named it llolotropis. I have, however, retained the former name, as having the claim of priority. |