MACROSAURUS. 15 
they had not come from the cervical or abdominal regions of the spine of the 
Mosasaur was satisfactorily proved by examples of vertebrae of the true Mosasaurus 
Maximiliani, from both these regions of the body, from the same deposits and 
locality. The difference in the forms and proportions of the vertebre in question 
with corresponding ones of the Mosasaurus having diapophyses from the sides of 
the centrum, and no hypapophyses, is so great, that I cannot refer them with any 
probability to the same genus: they might belong to the Mosasauroid genus Leiodon ; 
but in the absence of the confirmatory evidence of the teeth it seems preferable to 
refer the vertebra in question to a new genus, which I propose to call ‘ Macrosaurus,’ 
from the length of the body indicated by the proportions of the vertebre. I have 
no doubt, however, that it appertains to the Mosasauroid family of Lacertian Rep- 
tiles, not to the procelian Crocodilia.”* 
The collection of the Academy of Natural Sciences contains a number of vertebra, 
which appear to me to agree in character with those assigned by Prof. Owen to 
Macrosaurus, but I cannot avoid the suspicion that both the specimens in question 
and those described by the high authority just mentioned, really appertain to the 
dorsal series of Mosasaurus. 
Figures 19, 20, Plate VII, represent one of the vertebre referred to, from Free- 
hold, Monmouth County, New Jersey, presented to the Academy by Mr. O. R. 
Willis. The body measures three inches in length, and when perfect had its pos- 
terior convexity about twenty-seven lines high and wide. From the fore part 
projects, on each side, a robust, conoidal, transverse process, which, when entire, has 
measured an inch and three-quarters in length. 
Another specimen, represented in Figs. 1, 2, Plate III, is also from Monmouth 
County, New Jersey, and was presented to the Academy by C. C. Abbott. It pro- 
bably belongs to a more anterior position of the dorsal series than the preceding, 
with which it agrees in the size and form of the body. ‘The transverse processes 
have projected from the conjunction of the latter with the vertebral arch about the 
middle of the length of the body, and have been of robust proportions. The ver- 
tebral canal, preserved in the specimen, has its floor depressed towards the middle, 
and is seven lines high and ten wide at its entrance anteriorly. 
A similar, but somewhat larger dorsal vertebra has been described and figured 
by Prof. Emmons, in the North Carolina Geological Survey.* The specimen was 
obtained from the Green-sand of Cape Fear River, North Carolina, and has been 
referred by Prof. Emmons to Macrosaurus. 
A series of four mutilated dorsal vertebra, agreeing in form and construction 
with the preceding, from Burlington County, New Jersey, were presented to the 
Academy by Mr. L. 'T. Germain. The first has its body two inches and a half long, 
the others are slightly less. The first, when perfect, has had its posterior convexity 
about twenty-one lines in diameter; a second, which did not immediately follow 
the former, had its convexity about twenty-three lines wide, and nineteen high ; and 
1 Notes on Remains of Fossil Reptiles discovered by Prof. Henry Rogers, in Green-sand Forma- 
tions of New Jersey. Proc. Geol. Soe. Lond., 1849, V, 381, Plate XI, Figs. 1-6. 
2 P. 213, Fig. 34, a. 
