999 



Cope.] ^— ' [April 15, 



claws are compressed aud strongly curved, and capable of very extensive 

 flexion and extension. I cannot therefore agree with Prof. Marsh that 

 Ccelurus cannot be referred to any known order.:]: It is in fact allied 

 to Megadactylus (Hitchcock) from the Trias of 3Iassachusetts, differing 

 principally, so far as determinable, in the form of the condyles of the 

 femur. They are simple in Ccelurus, but in Megadactylus, the external 

 condyle has the double character seen in Megalosaurus.* 



The vertebrae are all of slender proportions, especially those of the neck 

 and tail. These, with most of the bones of the limbs, are hollow, having 

 large central cavities surrounded by thin walls, as in Megadactylus. The 

 parapophyses are confined to the anterior parts of the centrum. In the 

 cervical and dorsal vertebrae there is a conical fossa at eacli base of the 

 neurapophj^sis, which unite by their apices in the cervicals, forming a 

 canal distinct from that for the vertebral artery. The zygapophyses are 

 partly interlocking, having convexo-concave oblique articular surfaces. 

 There are four vertebrte of the sacrum (in T. bauri), whose arches are 

 coossified as well as the centra. The anterior caudal vertebrae only have 

 chevron bones. Prof. Marsh says they are wanting in the genus Ccelurus ; 

 but he does not appear to have possessed the most anterior of the series. 

 In neither species is there a distinct third trochanter of the femur ; but 

 there is not far below the great trochanter on the anterior face, a low 

 longitudinal, ridge-like angle. The femoral condyles have but little antero- 

 posterior extent, which implies but little flexure of the knee. 



The form seems to have been that of a terrestrial reptile which walked 

 readily on the hind legs, and was probably a great leaper. Tlie ex- 

 tremely long neck is a striking peculiarity, having proportions to the body 

 about like that of the swan. The habits were probably predaceous and 

 carnivorous. 



Three species are indicated by my collections. 



Char. Specif. Cervical vertebrae one-third longer than those of Ccelurus 

 fragilis Marsh, the sides of the centrum not sulcate, the anterior articular 

 face of an anterior centrum not convex. The faces are oblique, showing 

 that the head was carried above the level of the body. 



M. 

 Length of body of ? third cervical vertebra 063 



T^. , r . . (vertical 016 



Diameters of posterior cup -^ ^.^ 



^ ^ (transverse 019 



The dorsal centrum has subround articular faces, which are gently 

 concave, and a much contracted shaft. The section of the latter is sub- 

 round, a little flattened below. The inferior border of the neural arch 

 is coossified and extends well down on the side, its inferior border being 

 marked by an open longitudinal groove. On the superior border of the 

 middle of this groove is an indistinct tuberosity. Above this line at the 

 middle of the neural arch a thin longitudinal broken ridge probably repre- 



* See Cope, Trans. Amer. Philosoph. Soc., xiv, 1870. PI. xiii. 



