Prof. H. G. Seeley on Euskelesaurus Brownii. 329 



the form of the proximal end and position of the lateral 



trochanter. It is closely related to Massospondylus, but 



distinguished as a genus. The Zanclodonts are the nearest 

 European allies. 



Tibia and Fibula. 



These bones are represented by the distal extremities of 

 the bones of the right and left limbs and their proximal 

 extremities on the left side * of the animal. Mr. Brown's 

 specimens (20 a, 20 b), referred to (I. c.) as fragments of a 

 large metatarsal and metacarpal, I have been able to fit 

 together as portions of one bone, and have fitted this to the 

 hinder fracture of the left fibula, so as to complete the distal 

 end of that bone. Some matrix has been removed from the 

 proximal end of the tibia, to exhibit the contour of the head 

 of the fibula. It is possible that the anterior margin of the 

 fibula, as a consequence of injury, may have been anchylosed 

 to the tibia ; but its hinder portion is certainly free, and the 

 bone is displaced backward, while the surface of the tibia 

 beneath it in front has a fractured aspect. 



The Distal Ends of the Bones. 



The distal end of the tibia is of subtrapezoidal form, about 

 7 inches wide in front, parallel to the posterior surface, which 

 is narrow, with the external and internal sides of the bones 

 converging backward, and the margins rounded where the 

 two pairs of sides meet. The antero-posterior thickness of 

 the bone is 4 to 5 inches, the difference being due to con- 

 ditions of fossilization. The posterior and lateral surfaces 

 are of about the same width (3| inches). The lateral surfaces 

 of the tibia approximate towards each other as they ascend, 

 so that the transverse width of the shaft rapidly diminishes ; 

 and at the superior fracture, 5 inches above the transversely 

 truncated distal end, the distinction between the several sur- 

 faces of the bone is almost obliterated, the section being 

 subtriangular, with the angles well rounded, with a transverse 

 measurement of 3^ inches in the right tibia and 4 inches in 

 the left. 



The distal end of the fibula measures 5 inches from back 

 to front and about 2^ inches from side to side on its rounded 



* Professor Huxley (Quart. Journ. Geol. Soc. vol. xxiii. p. 4) describes 

 the distal end of the right tibia and fibula. The fibula is lost from this 

 specimen. Mr. Lydekker suggests that Prof. Huxley mistook the left 

 bone for the right ; but the right tibia and astragalus referred to are 

 described by Mr. Lydekker (it. 1625 c) as fragmentary undetermined 

 bones (Cat. Poss. Rept. Brit. Mus. Suppl. pt. iv. p. 253). 



