78 THE EXTINCT BATRACHIA, REPTILIA 



Measurements. In. Lin. 



Length of muzzle to 16th tooth, 1G 0.5 



" " " extremity of premaxillary bone, 7 1. 



" " " to posterior edge incisive foramen, 2 4.5 



" to anterior " " " 1 7.5 



Humerus. — This, with a femur, belongs to the right side of the series from Birmingham, first described. Its 

 characters are indicated under the head of T. brevispinis. The shaft is rather slender and curved outwards ; the 

 head is strongly curved backwards ; its articular face is narrow, and remarkably convex. The condyles are broken 

 away, leaving the comencement of the coronoid fossa : 



In. Lin. 



Length (restored), ■ 9 5 



" to summit deltoid ridge, 2 11 



Width head, 2 3 



Circumference shaft (least), 2 1 



Femur. — This piece is perfect ; two distal ends from Barnesboro, besides numerous proximal ends, have also 

 come into my hands. It is more slender than in the caimans and crocodiles of the present day. The inner trochanter 

 is quite prominent, the articular face of the head very convex. The shaft is sigmoidally bent anteroposterioly, and 

 is bowed extero-internally, with a subordinate abrupt incurvature below the head. The latter is largely caused by 

 a prominent thickening on the inner side. The outer condyle is twice the size of the inner, and they are continued 

 into obtuse crests on the upper face of the bone, of which the outer is much more elevated. Below their sides spread 

 apart. 



In. Lin. 



Length, 10 7 



" of head (straight), 2 7 



" (transverse) of condyles, 2 3 



Least circumference of shaft, 3 5 



Of dermal bones, those of two species, perhaps of more, were procured from the excavations that produced four 

 species of Gavials, with Bottosaurus,* and to which they are to be referred is not very clear. In the one, the pits 

 or fovea are very large and are separated by narrow elevated partitions ; in the other they are small and are separated 

 by fiat intervals wider than themselves. In the former the fovea extend to the edges of the plate on the bevelled 

 edges; in the latter, the bevelled edges are without fovae. Leidy says of those of this type, "plates coarsely 

 foveated." The first described belong to the median series of the present species, as they usually accompany its 

 bones when they occur alone; and the latter to the external series. 



Parallelogrammic dermal bones without pits, and with very high longitudinal crests, standing on more than half 

 the length, frequently accompany remains of this species. They are cervical or nuchal bones, and are of relatively 

 large size, equalling those of the dorsal region. The crests are oblique in the direction of their length. Such bones 

 belong to this species, perhaps to H. cordatus also. 



HOLOPS TENEBROSUS, Leidy. 



Crocodilus ienebrosus, Leidy. Cretaceous Reptiles U. S., 115. Tab. III., figs. 12-15. Thoracosaurus Ienebrosus 

 Cope. Geological Survey of New Jersey, Appendix C. 



This species is as yet little known. Leidy'stype is represented by two cervicals, a seventh dorsal, a caudal, and 

 portions of humeri ; on account of their close resemblance, and marked specific separation from H. obscurus, I regard 

 as the same an animal of which a cervical and three lumbars are preserved in my collection. The dorsals exhibit a 



* Several simple coprolites which accompanied these remains, probably belonged to the same species. 



