68 ARTICLES REFERRED TO IN THE SECRETARY'S REPORT. 
first noticed the species in 1824, is yet only known from several fragments of 
jaws, a few teeth, and vertebree, found in the green-sand of Burlington county, 
New Jersey. The specimens indicate this crocodile to have resembled in its 
construction and size the alligator of the Mississippi, or the crocodile of the Nile, 
more nearly than the Gangetic gavial. Several smaller species of crocodiles, 
with concavo-convex vertebree, or vertebrae of the same construction of those 
of living crocodiles, are indicated by specimens of vertebree and other bones 
found in the green-sand of New Jersey and Delaware. 
Another crocodilian reptile, the remains of which have been found in the 
ereen-sand of New Jersey, is the Hyposaurus Rogersti, named by Professor 
Owen, of London, after Professor Rogers, who submitted several vertebrae of 
the animal to his inspection about fifteen years ago. This crocodile belongs to 
a more ancient type of structure than the former ones, and has no near living 
representative. The vertebra have their bodies dished at both extremities, or 
biconcave, as in fishes, though in a much less degree. No considerable portion 
of the skeleton of this species has yet been discovered, and its remains are 
usually in an exceedingly friable condition. The author has had the oppor- 
tunity of observing specimens of vertebra, fragments of bones of the limbs, 
and teeth of about eight different individuals. The teeth are long, narrow. 
and curved conical like those of the Gangetic gavial, but are more or less com- 
pressed, so as to present anterior and posterior trenchant or cutting borders, 
The animal did not exceed in size the alligator of the Mississippi. 
Another crocodilian reptile, much larger than any of the preceding, and con- 
structed after a different type, has been named Discosaurus vetustus. Only 
vertebrae and some of the small bones of the limbs of the species have as yet 
been found. The bodies of the vertebra have their articular ends flat, or nearly 
so, and they bear a general resemblance with the corresponding portions of the 
vertebre of the living cetaceous, or animals of the dolphin and whale order. 
The genus is named from the articular ends of the vertebral bodies appearing 
as distinct disks or plates implanted on the latter. Remains of six different in- 
dividuals have been observed by the author from the green-sand of New Jersey 
and from other cretaceous formations of Georgia, Alabama, and Mississippi. A ’ 
few bones of a foot of this reptile from New Jersey indicate the limbs to have 
been constructed as fins, so that the animal was more eminently aquatic than 
the true crocodiles. 
An equally large crocodilian reptile with the one last indicated, and closely 
allied to it, as proved by the construction of the vertebrx, has been named 
Cimoliasaurus magnus, the generic term signifying its contemporaneous age 
with the chalk. The remains of this animal, consisting of a number of verte- 
bre, have as yet only been discovered in the green-sand of Burlington and 
Monmouth counties, New Jersey. 
To conclude with the American cretaceous crocodiles, a large tooth, belong- 
ing to the museum of the Smithsonian Institution, from a deposit of the Red 
siver of the North, indicates a peculiar species, to which the name of Pirato- 
raurus plicatus has been given. The specimen was found in association with 
a number of shark teeth, of species evidently of the cretaceous epoch. 
