THORACOSAURUS. 5 
SAURIA. 
THORACOSAURUS. 
Thoracosaurus neocesariensis. 
New Jersey Gavial, Dz Kay, Ann. Lyc. Nat. Hist. N. Y. III, 1833, 156, pl. iii, figs. 7-10. 
Gavialis neocesariensis, Dz Kay, Zool. New York, 1842, part III, 28, pl. 22, fig. 59. 
Crocodilus s. Gavialis clavirostris, Morton, Proc. Acad. Nat. Sci. Phila. III, 1844, 82.—Gresen, Fauna d. Vorwelt, 
1847, 122. 
Crocodilus basifissus, OwEN, Jour. Geol. Soc. Lond. V, 1849, 381, pl. x, figs. 1, 2; Paleontology, 1860, 277.—Picrer, 
Traité de Palwont. I, 1853, 482. 
Sphenosaurus, Acassiz, Proc. Acad. Nat. Sci. Phila. IV, 1849, 169. 
Thoracosaurus grandis, Lewy, Proc. Acad. Nat. Sci. Phila. VI, 1852, 35. 
The most characteristic of the Crocodilian remains, obtained from the strata of 
the Cretaceous period in the United States, consists of a nearly entire skull, which 
was discovered in limestone, overlying the ferruginous Marl, on the farm of Gen. 
William Irick, near Vincenttown, Burlington County, N. J. The specimen was 
presented by that gentleman, and Mr. Wm. Whitman, of this city, to the Academy 
of Natural Sciences, in the cabinet of which it is now contained. ‘This finely pre- 
served fossil consists of the skull, without the lower jaw. It has lost the anterior 
extremity of the muzzle, estimated to have been equal to half its original length. 
The teeth are also broken away, but sockets with the remains of fangs for fourteen 
of the back teeth exist on each side of the fossil. 'The zygomatic arches, as formed 
by the squamosals, are broken away, as is also the case with the articular ends of 
-the tympanics and the lower or outer conjoined extremities of the ecto- and ento- 
pterygoids. 
The matrix, in which the fossil was imbedded, for the most part has been chiselled 
away. Portions still adherent and occupying one orbit and palatine orifice, besides 
the interior of the cranium and nasal passages, consist of a moderately hard, gray 
arenaceous limestone. The bones of the fossil are brown and friable. 
In general shape and construction the fossil skull exhibits more resemblance to 
that of the existing Gavial of the Ganges (Gavialis Gangeticus) than of any other 
of the living crocodilian Reptiles, though from the non-eversion of the orbits and the 
more gradual prolongation of the muzzle it also presents a relationship to the genus 
Mecistops, of Western Africa. Of all known forms, however, it bears most resem- 
blance to the skull of the extinct Gavialis macrorhynchus, of the Cretaceous forma- 
tions of Europe. 
In consequence of the anterior extremity of the muzzle being lost in the New 
Jersey specimen, we have no positive means of ascertaining the length-of the skull. 
Supposing it, however, to have held the same relation of length to breadth as in the 
recent Gavial, in its perfect condition it would have measured about three and 
three-quarter feet in length and one and a-half feet in breadth. The relation of 
length to breadth in the Gavialis macrorhynchus, with which the New Jersey 
species appears to be most closely allied, is rather less, and would have made our 
