16 



UNDETERMINED CROCODILES. 



and portions of the others, but so far as it is preserved it corresponds in form with 

 that of the Alligator. The fifth dorsal has its body more compressed laterally than 

 in the specimen above described from Timber Creek, and the hypapophysis is abso- 

 lutely very much more robust than in the latter, though the vertebra is smaller. In 

 the Barnsboro' specimen the anterior articular concavity of the body is quadrilateral, 

 whereas it is broadly cordiform in the Timber Creek specimen. In the former the 

 hypapophysis is excavated in front ; in the latter it is plane. These differences in 

 two characteristic vertebrae are, perhaps, sufficient to indicate that they belong to 

 two species. 



Comparative measurements of the two vertebrae are as foUows : — 



Bakxsboro' Sp. Timber Ckeek Sp. 



Lines. Lines. 



Length of body inferiorly 20 22 



Length of body laterally 20 22 



Height of body anteriorly It 18 



Width of body anteriorly 16 22 



Thicliness of body at middle 12 17 



Thickness of hypapophysis ........ 9 6 



Breadth of vertebral arch laterally ...... 17 20 



Width of vertebral canal . 6 7 



Height of vertebral canal 7 8 



The specimen of the shaft of a femur is three inches and a third in circumference, 

 and resembles the corresponding portion of the same bone in the AUigator. 



The dermal bones are square, differ in size, and are coarsely foveated. Two of 

 them form a median elevation without being carinated ; the others are flat. One 

 of the more perfect measures two inches by twenty lines ; another measures two 

 inches eight lines by two inches. 



The museum of the Academy contains two mutilated bodies of posterior dorsal 

 or of lumbar vertebrae, of mature age, from ArneytoAvn, Burlington County, N. J., 

 presented by T. A. Conrad. The specimens, excepting in being devoid of the 

 hypapophysis, agree with the bodies of the dorsals above described, and are like 

 those in the Living AUigator. 



In the same museum there are the bodies of three vertebrae, which have lost 

 their arches at the sutural attachment, from JobstoAvn, Burlington County, N. J., 

 presented by Dr. E. Hallowell. One of the specimens, represented in Fig. 6, Plate 

 II, apparently of the fifth cervical vertebrae, is much less convex posteriorly than in 

 the specimens above described, and has its parapophysis wider and much less 

 robust. Its hypapophysis is a small longitudinally cleft tubercle. The body is 

 nineteen lines long, sixteen wide anteriorly, and fifteen high. The remaining 

 specimens are the bodies of two posterior dorsals or lumbars, twenty lines long, and 

 resemble the corresponding bones in the living Alligator. In the same collection, 

 and from the same locality and donor, there is another specimen consisting of the 

 body of a posterior dorsal vertebra witli the coosificd abutments of its arch remaining. 

 The body agrees in its form and proportions with those just described, and measures 

 twenty-one lines in length. 



The body of a posterior cervical vertebra, from the Green-sand of St. George's, 



