Thecodontosaurus and Palaeosaurus. 147 



of the ilium rather longer and deeper, though these differences 

 are no more than might be attributed to age. Since the teeth 

 of Zanclodon appear to be of the same general type as that of 

 Falceosaurus platyodon, there is strong probability that this 

 ilium is rightly referred to Falceosaurus. 



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 process 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 Palreosaurus. 



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 tlie ilium of 

 Thecodontosaurus when divested of matrix. 



The bones have unfortunately become scattered, so that the 

 unique treasures, wliich derive their chief value from being 

 naturally associated portions of skeletons, can never again 

 be brought together. The 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 vertebri.e, scapula, 

 and apparently the coracoid, humerus^ ulna, metacarpals, 

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

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

 humerus, and ulna; and upon them the dimensions of the 

 animals must be based. 



The vertebri» are short and slender relatively to the length 

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

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

 Saurischia. 



There is a somewhat elongated specimen in the Bristol 

 Museum named cervical vertebra, which does not show any 

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

 maining ten vertebrae are dorsal and caudal. It is impossible 

 to distinguish the genus to which they belong, though the 

 characters of the sacrum make it probable that they belong 



* I have not seen the sacrum. It is figured in Quart. Journ. Geol. 

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



