HTPOSAURUS. 19 



Remains of this genus, on several occasions, have come under my notice, but 

 usually in a much mutilated condition. 



A small collection of bone fragments, referable to this animal, Avere found in the 

 Green-sand, near White Horse, Camden County, N. J., and were presented to the 

 Academy of Natural Sciences by W. Parker Foulke. The specimens are exceed- 

 ingly friable, and consist of portions of several vertebrae, small fragments of a skull 

 together with portions of the supra-angrdar bones of the lower jaw, fragments of a 

 humerus, portion of a cervical rib, and the crowns of five teeth, all appertaining to 

 a single individual. 



One of the vertebral specimens, of the proportions of those referred by Prof. 

 Owen to Hyposaums, from the anterior part of the dorsal series, consists of the 

 fragment of a body retaining one of the sub-concave articvdar faces, and the remains 

 of the large lamelliform hypapophysis projecting like a keel from the bone inferiorly. 



The best of the vertebral specimens consists of the body of a cervical vertebra 

 with one abutment of the arch remaining. Its articular faces are half oval in out- 

 line, with the anterior one more deeply concave than the posterior, which is like- 

 wise the case in the other vertebral specimens. The length of the body is about 

 two inches and a half, its depth posteriorly twenty lines, and its width above seven- 

 teen lines. Ifs sides are deeply impressed ; its surface next the vertebral canal is 

 nearly plane. The transverse processes are of robust proportions, and those below 

 are united by a stout hypapophysis bounding the fore part of the body beneath. 

 Posterior to the hypapophysis, the under surface of the body forms a deep con- 

 cavity subdivided by a slight median carina ending in an angular apophysis poste- 

 riorly. 



The supra-angular bone is quite peculiar, and appears to have largely contributed 

 to the articulation of the lower jaw, though this is not certain, as the condition of 

 the specimen is such that I am not positive whether the articular surface preserved 

 in the fragment actually belongs to the supra-angular. Internally to the articular 

 surface there is a large vertical sutural surface, either adapted to a true articular 

 bone, or unlike the arrangement in any other known Crocodilian, it must have 

 joined the splenial bone as in Turtles. Exterior to and in advance of the articvda- 

 tion of the lower jaw, the supra-angular forms a strong projecting ledge Avhich 

 overhangs the exterior surface of the bone and gradually diminishes over the 

 position of the oval foramen. 



The fragments of the humerus mentioned are too much injured to derive any 

 character of importance from them. 



Of the five crowns of teeth belonging to the collection the two best preserved 

 are represented in Figs. 16, 17, Plate HI. The largest resembles the teeth of the 

 Gavial, being curved conical, nearly circular in transverse section, with prominent 

 acute ridges defining the outer and inner surfaces, which are distinctly fluted. The 

 smaller specimen, and such also is the character of those not represented in the 

 plate, differs from the preceding in being compressed from without inwardly, so 

 that its transverse section exhibits an oval outline, and it is less distinctly fluted. 



Recently Dr. W. W. Lamb presented to the Academy of Natural Sciences a 

 collection of bones, referable to a single individual of Hyposaurm, from the Green- 



