1 170 



CLASS REPTILIA. 



pes have only three functional digits ; the astragalus being closely 

 applied to the tibia. The teeth and pelvis approximate to the 

 Megalosaurian type. Compsognathus was about two feet in total 

 length ; and undoubtedly hopped on its pelvic limbs, after the 

 manner of a bird. Hallopus is one of the few Dinosaurs with only 

 two sacral vertebrae ; the number of those of Compsognathus being 

 unknown. 



Family Ccelurid^e. — This family is represented by comparatively 

 small forms, ranging in size from five or six to about twelve feet 

 in length. They are characterised by the vertebrae and ribs being 

 completely honeycombed by cavities, communicating with a small 

 aperture on the side of the centrum. The cervical vertebrae (fig. 

 107 1 ) are typically longer than the dorsals, and have the ribs 

 anchylosed to the arch and centrum, and the neural spine reduced 

 to a mere ridge. The limb-bones are hollow, and the pelvis is of 



v r -z 



Fig. 1071. — Anterior and left lateral aspects of a cervical vertebra of Calamospondylus Foxi; 

 from the Wealden of the Isle of Wight. Two-thirds natural size, prz, Prezygapophysis ; ptz, 

 Postzygapophysis ; r, Rib (restored) ; f, Pneumatic foramen ; s, Neural spine. 



the ordinary Theropodous type, with a very long pubic symphysis. 

 The type genus Coslurus, typically from the Upper Jurassic of 

 America, but also occurring in the English Wealden, has the 

 cervical vertebrae greatly elongated, the first few being opistho- 

 and the remainder amphiccelous. In Calamospondylus (fig. 107 1) 

 the cervicals were shorter, and were probably all opisthoccelous ; 

 the one known species being from the English Wealden. Pro- 

 fessor Cope includes in this family other small Dinosaurs from 

 the Trias of North America, which he identifies with Tanystro- 

 phceus, originally described on the evidence of extremely elongated 

 caudal vertebrae from the German Muschelkalk, once referred to 

 the Sauropterygia. In these forms all the cervical vertebrae were 

 amphiccelous ; and the femur has an inner trochanter. Mega- 

 dactylus, which Professor Cope regards as identical with these 

 forms, is, as already mentioned, identified by Professor Marsh with 

 Anchisaurus. 



Suborder 3. Sauropoda. — With the third and last suborder we 



