AND AVES OF NORTH AMERICA. 



65 



The most perfect tooth is slender and curved, and bears much resemblance to those of Holops obscurus. 

 The section of both root and crown circular, the latter regularly acuminate, and furnished with delicate cutting 

 ridges. Terminal half smooth, basal half with a silky striation. Fang as well as crown strongly ourved. Cutting 

 ridge descending as far on the posterior, as the anterior aspeot of the crown. In a fractured New Jersey tooth, 1 

 count three dentinal cones. In one from Maryland, four. The inner cone is weakly [luted in both, but it scarcely 

 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 all about one-half the same. Teeth 

 IVom other portions of the jaw arc but litle stouter. 



In. Lin. 

 3 8. 

 (i.O 



Length of tooth from New Jersey, (on curve,) 



Diameter at base crown. 

 Length of Maryland specimen 16.5 lines. Base of crown, lines. 

 Miocene of New Jersey and Maryland. 



THECACHA M I'M A SQUA N K ENSIS, Marsh. 



Billim. Anier. .lourn. Sci.Arls, 1869, p. 391. 



The enamel of the crowns of the teeth, is in this species quite rugose. The cutting edges arc short, and promi- 

 nent, ; the genera] form cylindric and but little curved. 



Miocene, of Squankum, Monmouth Co., N. J. Mus. 0. C. Marsh. 



* 



T 1 1 E( IACHA M PSA V A STIQ I ATA, Leidy. 



Croeodilw fastij/iatus, Leidy. Proc. A. N. S., Phil., 1851, 827. 

 From Eocene of Eastern Virginia. 



BOTTOSATTRUS, Agaesiz. 



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 vertebf£e, and their substitution by low transverse or divided 

 elevations. It also appears that the greal external foramen which separates the angular, 

 dentary and articular bones was closed up. 



BOTTOSAURTTS HARLANI, Meyer. 



Orocodilus harlani, Meyer Palaeologioa, 1832, LOS. Crocodilus maororhynchm, Harlan. Jour. Ac, N. Sol., Phil., 

 1824, 15 (name preoccupied). Bottomurw harlani, Agassi/.. Leidy, Cretaceous Rept. N. km., 12-14, Tab. 



The teeth of this species 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, N.J. They consist, of various fragments 

 of cranium with dermal plates. A tooth is compressed, but has a short conic acute, crown, snob as has not before 



been seen in this species. 



The inlerorbilat region is strongly pitted medially, and exhibits on each side a. de.-p, short groove. There are no 



marked crests. 



AMEIU. PHIL080. SOO. — VOL. XIV. 11 



