316 PROCEEDINGS OF THE ACADEMY OP under the name of Mustela angitstifrons. Similar ridges, relatively less well-developed, exist in the Gray Fox. The orbits are as little distinct from the temporal fossae as in the Skunk or the European Hedge-hog. The cranium back of the orbital spaces is conoidal and wider than high. It is narrowest just back of the postorbital eminences ; relatively not so much constricted as in the Mink or Fox, though more than in the Skunk or European Hedge-hog. The face is long, and tapers evenly to the end of the snout. The palate is long, narrow and moderately arched, and exhibits no large perforations as in the Opossums. Tlie fossil retains most of the teeth, the number of which consists of seven molars, a canine and two incisors. Of the molars the posterior four have broad trilateral crowns, with a num-ber of points or tubercles, as in the Opossums and Hedge-hogs, or the back two in the Dog. The anterior three molars have simple, compressed conical crowns. The canine is comparatively small. Whether the animal possessed more than two incisors on each side is uncertain. Measurements from the specimen are as follows : Estimated length of skull from occipital foramen to fore part of incisive alveoli 29 lines. Length of cranium from inion to fronto-nasal suture 18^ " Breadth at zygomata.. 17^ " Length of palate 15| " Length of molar series 11 " IcTOPS Dakotexsis. This name is founded on a small fragment of a skull which was obtained with the preceding. At first the specimen was supposed to bHlong to the same animal as the former. It clearly indicates a skull of nearly the same size and shape as that oi Leptkiis. The fragment consists of a portion of the face, containing the remains of most of the molar teeth. The face appears to have had nearly the same form and construction as in Leptictis, and the forehead exhibits traces of the two peculiar ridges defining the upper part of the temporal fossa? in the latter. The remains of the molars consist of the posterior six. The second pre-molar appears to have been a two-fanged, conical crowned tooth, as in Lep-tictis. The third premolar has a trihedral crown, inserted by three fangs, whereas in Lepticti'i, as in the preceding tooth, it has a simple conical, crowu with a pair of fangs. The crown of the third premolar of Ictops is composed of three principal lobes, two external and the third internal. The four back molars have the same relative position and size as regards one another as in Lepliclis, but they do not project abruptly beyond the premolars externally as in this. Their crowns, so far as can be ascertained, appear to have had the same construc-tion as in the third premolar. The space occupied by the back six molars in Ictops is ten lines, being a little more than in Leptictis. Observations oa REPTILES of the Old World. Art. II. BY E. D, COPE. Chxm.ele'O BAsiLTscrs Cope, sp. nov. This species pertains to group st. of Gray's arrangement of the species of this genus (Proc. 2ool. Soc. Lond., 1864), that is, is nearest allied to 0. V e r ru c o s u s Gray, and C. calyptratus A. Dum. It has therefore a 'high longitudinal crest on the supraoccipital region, and the supraoccipito-mastoid crest is not furnished with any dermal margin of flap behind, but is 4be margio of a truncate face which is minutely scaled. No dorsal or ven-[Dec.