196 



THE EXTINCT BATRACHIA, REPTILIA 



MOSASATTRUS OARTHRUS, Cope. 

 Spec. now 



This species is indicated by fragments of the jaws and teeth, with an imperfect quad- 

 rate bone and vertebrae of one individual, and vertebree and jaws of a second and larger, 

 from the green sand of New Jersey. 



The animal as indicated by the above specimens, was of about the size of M. giganteus, perhaps nfty-five feet in 

 length. Us i ransversely oval centra ally it to the M. depressus and M. missuriensis. The quadrate bone distinguishes 

 it from the former of these, as it, more nearly resembles that of the M. dekayi. 



The depression of the articular surfaces is uot quite so great as in the M. depressus. The diapophyses of the cer- 

 vicals have much antero-posterior extent, and very little vertical. The hypapophyses are well developed. The sur- 

 face of the centrum is very coarsely striate or rugose in front of the diapophyses; the posterior portion near the ball 

 is longitudinally striate. 



Length centrum, median cervical, 

 Diameter cup, transverse, 

 " " vertical, 



Linen. 



4.8 



85.6 



28.6 



The superior rim of the cup is excavated openly, by the neural canal. The lateral element of I, he alias has the 

 same form and size as in the M. dekayi. The left os quadratum presents several peculiarities, intermediate perhaps 

 between those of M. dekayi and ML depressus. The median posterior ridge and knob are so prominent as to include 

 eei w een I .hem a dee]) groove whieh commences at the pit and expands below, ceasing with the extremity of the ridge. 

 The latter terminates rather abruptly, somewhat as in M. maximus, but is not truncate, terminating in an oblique 

 keel. Prom the knob downwards the hone is longer than in M. dekayi. and the outer distal longitudinal ridge so 

 marked in that species, is either very short, or wanting. The inferior extremity of the angle being broken away, its 

 absence cannot be asserted, but it does not appear at a point considerably below its origin in M. dekayi. In the lat- 

 ter species also, the median posterior ridge is very small, and though the extremity is broken off, there is no ridge as 

 a basis for the prominence seen in the present animal. The external angle of the proximal extremity is not as promi- 

 nent in this species as in M. dekayi. 



In,. I An. 



Length of quadratum, (i 3 



" to knob, (apex) 48.6 



" * extremity median post., ridge, 55.5 



The development of the median posterior ridge carried a little further, viz: to beyond the. pit, to the outer side. 

 throwing it in towards the meatus, constitutes the peculiarity of this element in Mos. depressus. 



The crown <^' I lie teeth of this specimen were broken away when I obtained them; the falsi! roof of oik! of them 

 measures eighteen lines in diameter. The second and largest Specimen, which was found some three years after 

 wards, Was not. more fortunate, as the workmen broke off the crowns of its teeth also. 



This speeios was found at the base of the upper green-sand bed of the upper creta- 

 ceous of New Jersey, near Barnesboro, Gloucester Co. It was discovered by my friend, 

 I. C. Voorhees, to whom I am indebted for the type specimens. 



MOSASAURUS DEPRESSUS, Cope. 



Geological Survey of New Jersey, App. ('. 



The remains characteristic of this species consist of cervical, dorsal, and lumbo-sacral vertebra;, and some pieces 

 of the cranium, including os quadratum, from Burlington Co., N. J., in the museum of the Academy, from Lewis T. 



