MACROSAURUS. 75 



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 vertebrae 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 

 i-efer the vertebrae in question to a new genus, which I propose to call ' Macrosaurus,' 

 from the length of the body indicated by the proportions of the vertebrae. I have 

 no doubt, however, that it appertains to the Mosasauroid family of Lacertian Rep- 

 tiles, not to the procaelian Crocodilia."^ 



The collection of the Academy of Natural Sciences contains a number of vertebrae, 

 which appear to me to agree in character Avith 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 vertebrae referred to, from Free- 

 hold, Monmouth County, New Jersey, presented to the Academy by Mr. O. E. 

 "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 Kiver, North Carolina, and has been 

 referred by Prof. Emmons to Macrosaurus. 



A series of four mutilated dorsal vertebrae, 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 foUow 

 the former, had its convexity about twenty-three lines wide, and nineteen high ; and 



' Notes on Remains of Fossil Reptiles discovered by Prof. Henry Rogers, in Green-sand Forma- 

 tions of New Jersey. Proc. Geol. Soc. Lond., 1849, V, 381, Plate XI, Figs. 1-6, 

 = P. 213, Fia;. 34, a. 



