in North America of rare Extinct Vertebrates. 213 



We may assume that the femur of Chondrosteosaurus was 

 discovered by Mr. Lucas in such contiguity with the other 

 sufficiently characteristic and previously characterized bones 

 of that genus as to justify the following description of such 

 bone by Prof. Cope : — 



" The femur is long and without prominent third trochanter, 

 this process being represented by a low ridge. The condyles 

 have an extensive posterior sweep, and are separated by a 

 shallow trochlear groove in front "^. 



In Scelidosaurus also the process called "third trochanter" 

 in Iguanodon is reduced to^ or represented by, a ridge from 

 near the middle of the inner side of the shaft f ; and " the 

 condyles are but feebly indicated by a shallow notch on the 

 fore part, but more distinctly behind, where they are produced 

 backward "J. 



In the absence of a figure of the femur of Chondrosteosaurus ^ 

 we may infer that, amongst known Dinosaurs, it most resem- 

 bled that of Scelidosaurus. The main difference is in size. 

 The femur of Chondrosteosaurus is, in length, 1820 millims., 

 that of Scelidosaurus is 403 millims. 



" The tibia of Chondrosteosaurus j^'' like that of Scelido- 

 saurus, " is much shorter than the femur "§ ; and " the astra- 

 galus is evidently distinct from it " ||, as it is, likewise, in 

 Scelidosaurus*^ J in which, however, I consider the naviculare 

 and the ento- and mesocuneiform tarsals, in mammals, to have 

 coalesced with the astragalus. 



Prof. Cope figures the right scapula of Chondrosteosaurus j 

 and gives the following description : — " The scapula is rela- 

 tively of large size. It is rather elongate, and the superior 

 extremity is expanded. There is a very large mesoscapular 

 process, which is wanting in Cetiosaurus, according to Phil- 

 lips's figures. It appears to resemble the scapula in Dystropheus. 

 (See Report of Lieut. Wheeler, vol. iv. pi. Ixxxiii. p. 31). 

 The two proximal faces, the glenoid and the coracoid, are well 

 distinguished ; and their surfaces are, like the corresponding 

 faces of other bones, pitted coarsely "■^■^. 



Besides the scapula of Cetiosaurus^'\ , that of Iguanodon\\ 

 and of Scelidosaurus are sufficiently entire to be comparable 



* Proc. Amer. Philos. Soc. 1877, p. 236. 



t Monogr. 1855, pi. x. 63, t. 



X Ibid. p. 15. 



§ Cope, Proc. Amer. Phil. Soc. 1877, p. 236. 



II Id. ibid. 



^ Monogr. 1855, pi. x. a. 



** Proc. Amer. Philos. Soc. 1877, p. 236. 



tt Monogr. 1875, p. 32, fig. 2. 



XX Hist, of Brit. Fossil Reptiles, pt. vi. 1855, pi. 19. %. 1. 



