"The generic characters are apparent in the very unequally sized teeth with round section. The portion upon which the species is based is a part of the right ramus of the mandible, which is in the specimen viewed from the inner side. The jaw is obliquely and smoothly truncated from below, for the symphysis and surface of the bone is smooth. There is a very large tooth near the extremity of the dentary bone. Behind it is an interval equal to three times the diameter of its base, which is followed by a tooth of about one-third the length of the first tooth. Posterior to this one are two teeth of the same size as the second, all being separated from each other by about a tooth's diameter. These are followed by three subequal teeth of about two-thirds the length of the first tooth, and separated by about their own diameter from each other. They are all perfectly straight, very acute, and without the trace of a cutting-edge. The inflection-grooves extend to or a little beyond the middle of the length." The present species is smaller than the type of _Anisodexis imbrecarius_ from the Texas Permian, to which genus Cope originally referred the present species, and the apices of the teeth do not display the opposite cutting-edges seen in the Texas form. Measurements of the Type Specimen. mm. Length of jaw, including 7 teeth 31 Depth of ramus at second tooth 10 Length of first tooth 10.5 Length of third tooth 3.5 Length of sixth tooth 7.5 Skin of Sauropleura Sp. Moodie, Bull. Am. Mus. Nat. Hist., XXVI, p. 355, pl. lx, fig. 1, 1909. The present specimen is interesting on account of the presence of what I take to be a portion of the skin, which is preserved as a smooth mold over the ribs and ventral scutellæ. The skin was undoubtedly that of the back, since the creature is preserved on its belly, and is interesting in not showing the slightest trace of scales or other hard plates. The ventral scutellæ are characteristic of the species of the genus _Sauropleura_. With one species of this genus, _Sauropleura scutellata_ Newberry, the writer has found associated scutes of some size, and the same fact has been noted by Cope. =Genus SAURERPETON Moodie, 1909.= Moodie, Jour. Geol., XVII, No. 1, p. 80, fig. 23, 1909. Type: _Saurerpeton latithorax_ Cope. This generic name is erected for the reception of a single species described by Cope in 1897. The name is made necessary by the wide divergence of the characters exhibited by the present species from those of the species of the genus (_Sauropleura_) to which Cope (176) referred this species. The form is not a member of the genus _Sauropleura_, for reasons given below.