Tliecodontosaurus and Palaeosaurus. 147 



of the ilium rather lonjj^or and deeper, though tiiese differences 

 are no more tlian mi^ht he attributed to age. Since the teeth 

 of Zauclodon appear to he. of the same general type as that of 

 Pidd'osdurus pluti/odon, there is strong probability that this 

 ilium is rightly referred to Rdiposnuras. 



The second example in slab 63 is a mould from the internal 

 surface of an ilium. It closely resembles in contour the ilium 

 of an alligator. The acetabulum appears to be more nearly 

 closed than in the first specimen, and the anterior contour of 

 the pubic j)rocess is convex from above down, instead of being 

 straight, and it appears to be relatively wider than the ischiac 

 process. Hence, although the bones are right and left, are 

 similar in size and general form, and occur in proximity in 

 the same slab, it cannot be inferred that they belong to the 

 same individual or the same species of Palrcosaurus. 



There is a slab in the Bristol Museum containing a bone 

 which is broken at each of its four extremities, at present 

 without number, which may possibly prove to be the ilium of 

 l^hecodontosaurus when divested of matrix. 



The bones have unfortunately become scattered, so tliat the 

 unique treasures, which derive their chief value from being 

 naturally associated portions of skeletons, can never again 

 be brought together. Tiie Bristol collection is by far the 

 most important. Some of the bones, like the scapula and 

 femur, differ considerably in size. The bones retained at 

 Bristol comprise dorsal, sacral *, and caudal vertebrae, scapula, 

 and ap])arently the coracoid, humerus, ulna, metacarpals, 

 ilium, femur, tibia, fibula, metatarsals, and phalanges. The 

 bones which are fairly complete are the ilium, femur, tibia, 

 humerus, and ulna ; and u[)on tlicm the dimensions of the 

 animals must be based. 



Ihc Vertebra'. 



The vertebraj are short and slender relatively to tiie length 

 of the limb-bones; and the tail gives no indication of large 

 size of the bodies of the vertebraj, which is seen in some 

 Saurischia. 



There is a somewhat elongated specimen in the Bristol 

 ]\luseum named cervical vertebra, wliich does not show any 

 typical characters of that region of the skeleton. The re- 

 maining ten vcrtebrie are dorsal and caudal. It is impossible 

 to distinguish the genus to which they belong, though the 

 ciiaracters of the sacrum make it probable that they belong 



» I have not seen the sacrum. It is Hj^'ured in Quart. Jouru. Gool. 

 Soc. vol. XXVI. pi. iii. liga. 9, 10. 



