Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/89

 AND AYES OF NORTH AMERICA APPENDIX TO THE CROCODILIA. PEROSUCTIUS, Cope. Proc. Acad. N. Sci., Phila., 1868, p. 203. 83 Characters.—Toes 5-4, with claws two-three. No osseous nasal septum or bony eyelid. Belly protected by series of osseous plates, as well as the back. All the genera of Crocodiles hitherto known as living, are characterized by the possession of three claws on the fore-foot. The present therefore offers a remarkable exception. The free fingers and half webbed toes, and the bony abdominal buckler, together with the cartilaginous nasal septum, are points of strong resemblance to .Jacare (Gray including Caeman. Gray) but it differs from these creatures in the lack of bony orbit. In specific characters it differs from those of this genus which it most resembles—as J. nigra, in the absence of a transverse bony ridge between the orbits. Anotber feature of importance is the relation of the canine teeth of the lower jaw to the upper. On one side this tooth is received into a notch as in Crocodiles, on the others, it enters a pit of the maxillary bone, within the border of the same as in Alligators ! This remarkable combination may be abnormal even in this species, but this cannot he now ascertained, as it rests at the present time on a single specimen only. As its affinities are rather more Alligatorial, I am disposed to anticipate that the dental arrangement of the latter animals will be most common. Fig. 21. Fig. 22. Fig. 23. Fig. 24. PEROSUCHUS PUSCUSI Cope. Char. specificus.—Nuchal plates in a cross row of six ; cervicals in four cross-rows, all of four plates except the last of two. Dorsal plates in six—in a few eight in each transverse row. No posterior crest on arm or leg. Tail short with remarkably low crest. Muzzle broad fiat. without any ridges ; its width at the eighth tooth entering 1.4 in length from end muzzle to anterior margin of orbit. Description.—The specimen in the Museum of the Academy is young, measuring only 2 feet 5 inches in length. Of this the skull measures to the margin of the supra-occipital 2 in. 10.5 lilies ; and the tail to the vent 13 in. 7 lin. From groin to heel 3 in. 2.5 lin., and the hind foot 3 in. 7.5 lin. The. muzzle is a broad ovate, the sides rather more convergent anteriorly than in the Alligator missistWiensis. There is a thickening in front of each orbit, and