AND AYES OF NORT11 AMERICA. 65 The most perfect tooth is slender and curved, and bears much resemblanre to those of Ilolops ollsenrus. The section of both root and crown circular, the latter regularly arin»inate, and furnished with delieate cutting ridges. Terminal half smooth, basal half with a silky striation. Fang as well as crown strongly enrveil. Cutting ridge descending as far on the posterior, as the anterior aspect of the crown. Ina fractnred New Jersey tooth, count three dentinal cones. In one from Maryland, four. The inner cone is weakly fluted in both, but it soa•cely affects the form of the enamel. The typical tooth of this species. as compared with the T. antiqua, is more slender and curved. In a length of crown and fang slightly exceeding the largest of the latter, the diameters are 01 about one-half the same. Teeth from other portions of the jaw are but litle stouter. Length of tooth from New Jersey, (on curve,) Diameter at base crown. Length of Maryland specimen 16.5 lines. Base of crown, 9 lines. Miocene of New Jersey and Maryland. THECACHAMPStt. SQUANKENSIS7 Marsh. • Sillim. Amer. Journ. Sei.Arts, 1869, p. 391. bas Lin. 3 8. 6.0 The enamel of the crowns of the teeth, is in this species quite rugose. The cutting edges are short, and promi-nent ; thegeneral form cylindric and but little eurved. Miocene of Squankum, Monmouth Co., N. J. Mus. 0. C. Marsh. THECACHAMPSA. PASTIGIATA, Leidy. Crocodilus fastiuiatus, Leidy. Proc. A. N. S., Phil., 1851, 827. From Eocene of Eastern Virginia. BOTTOSAURUS, .Agassiz. The characters of this genus have never been pointed out to the knowledge of the writer. In the general form of the under jaw and teeth it does not seem to differ from Alligator. One character which separates it from that genus appears to be similar to that which distinguishes Thoracosaurus from Gavialis, i. e., the absence of long simple hypapophyses on the cervical vertebra, and their substitution bV low transverse or divided elevations. It also appears that the great external foramen which separates the angular, dentary and articular bones was closed up. BOTTOSAURUS HATILANI, Meyer. Crocodilus karlani, Meyer Palaeologiea, 1832, 108. Crocodilus 9nacrorklinchus. Harlan. Jour. Ae. Sci., Phil., 1824, 15 (name pre-occupied). rottosazt•uR harfaa. Agassiz. Leidy, Cretaceous Rept. N. Am., 1•-14, Tab. The teeth of this speeies are similar to those of Alligator in the short obtuse crowns. The pulp cavity is remark-ably large and extends into the crown, leaving the dentine and enamel at the apex little thicker than the sides. Besides the remains described by Leidy, portions of a smaller, perhaps younger, individual have been presented to the Academy of Natural Sciences by Dr. Ashhurst, from near Birmingham, it J. They consist of various fragments of cranium with dermal plates. A tooth is compressed, but has a short conic acute crown, such as has not before been seen in this species. The interorbital region is strongly pitted medially, and exhibits on eaeh side a deep, short groove. There are no marked erests. AMERI. PHILOSO. SOC.-VOL. :Kit it
