66 THE EXTINCT BATRACHIA, REPTILIA 



The dermal plates are about the size of Holops obseurus, but have smaller pits, wider intervals, and one margin 

 without pits, but smooth and thinned out. 



Lines. 

 "Width ramus where tooth series turns from inner to outer margin, 14.5 



" interorbital space, 14. 



" articular facet of mandible, 19. 



Length dermal bone, 25. 



It is difficult to refer vertebra to this species with certainty, as they resemble so closely those of Holops. The 

 species is less abundant than those of the latter, and being found with them the vertebra?, are easily confused. It is 

 not impossible, for instance, that those referred to H. tenebrosus belong to this animal, as teeth of the latter were 

 found near the same time and place. There have, however, come under my observation some vertebrae different from 

 those of any of the Holopes, which correspond in size and rarity with the present crocodile. A description is 

 therefore appended. 



First — These are a fourth cervical vertebra, and some long bones, which were presented together to the Burlinir- 

 ton County, N. J., Lyceum, and were procured at Gaskill's excavations near Birmingham in the same county. 



The vertebra differs much in form from other species here described, and though absolutely larger than those of 

 T. neocaesariensis, the neural arch was not coossified with the body, indicating the immaturity of the individual. 



The body is but slightly concave between the planes of the parapophyses, which are not at all directed down- 

 wards ; the latter are very short, and their articular faces are directed posteriorly and outwards anteriorly, the 

 posterior portions being connected by a high crescentoid ridge r whose anterior margin approaches within three lines 

 of the rim of the articular cup ; behind, a weak median keel connects it with the body plane, which is succeeded by 

 a prominent tuberosity close to the posterior shoulder. The anterior parapophysial articular surface extends without 

 constriction to the rim of the cup. The floor of the posterior half of the neural canal is broken away, revealing a 

 wedge-shaped chamber, which extends posteriorly and outwardly nearly to the shoulder. 



In. Lin. 

 Total length, 2 10. 



Length to shoulder, 2 3. 



Width of cup, 1 8. 



Vertical diameter of cup, 1 6.75 



" " to edge of parapophysis, 2 



"Width between parapophyses near cup, 1 10. 



" " " at posterior angle, 2 1. 



Length from post, angle parap. to shoulder, 1 1.25 



Length from post, angle parap. to cup, 1 2.5 



The radii of the median area of articulation are numerous, 1,34), fine and equal ; the transverse rugae of the 

 anterior area are also fine, thirteen in number. 



Portions of femur, tibia, humerus, and ribs were in the same lot with the above described vertebra; they 

 resemble the cervical vertebra in color and in the bright green of the matrix which adheres to them externally, as 

 though they had been wet ; their size relates so as to render their appertainance to the same animal probable. They 

 indicate an animal of large size. 



The shank of the femur is cylindrical at its middle ; the prominence of the anterior flexure is situated well below 

 the head, while the head itself is not as broad as in some species (e. g. Crocodilus tiporcatus). An obtuse ridge 

 runs from behind forwards and downwards across the outside face of the shaft, transferring the position of the 

 steepest face from the back to the front aspect. On the inner face the trochanter is small, and the surface is swollen 

 near the upper edge at the flexure. 



Compared with the shank of the femur of Hyposaurus rodgersi, the present is less depressed and lacks a longi- 

 tudinal concavity, with obtuse elevated margins, near the superior flexure, which is characteristic of that species. 

 For a considerable proximal portion of the femur, the medullary cavity is quite small ; at the middle it is much 

 larger, and the walls quite thin : measurements are, 



