﻿KIMMERIDGE CLAY. 



Crocodilians than in Lacertians. There is no evidence or indication that these haemapo- 

 physes were disposed otherwise than in the rest of the Reptilian class, meeting, each pair, 

 at the medial line, with a space between ischia and pubes, answering to a common and 

 uninterrupted obturatorial vacuity. This space, in Dicynodon, is obliterated by continuous 

 ossification. 



The length of the pubis in Omosaurus is 3 feet 6 inches, the extreme breadth is 

 9 inches ; the least breadth of the pre-pectineal part ( s ) is 3 inches 6 lines ; the extreme 

 thickness of this part is 1 inch 3 lines. 



§ 14. Femur. — To the right of the pelvis lies the femur of the same side, with the 

 hinder surface exposed (PI. XIX, 65). The head (a) of the bone is at a distance of 

 1 foot 8 inches from its socket (<?) and a little posterior to it. The distal end lies 

 exterior to and a few inches in advance of the right ilium. The terminal articular 

 surfaces of the shaft are, to some extent, worn away, but sufficient remains to show that 

 the chief convexity or head {a) projected some inches within the inner longitudinal border 

 of the shaft, the proximal surface sloping slightly distad to the rough convex angle, 

 representing a trochanter (6), from which a thick rough ridge is continued, gradually 

 subsiding upon the shaft. 



The breadth of the proximal end of the bone is 1 foot 1 inch ; at 1 foot distance 

 from that end the shaft is contracted to a breadth of S inches, and at its middle part to 

 one of 6 inches. Notwithstanding the posthumous pressure which has shattered this part 

 of the crust of the femur, one may infer that the shaft was naturally subcompressed 

 from before backward. 



At three fourths of the distance from the head of the bone the shaft again begins to 

 expand, attaining at the distal end a breadth of 13^ inches. There is a distinct oblong 

 protuberance (<?) at the inner and back part of the shaft, 1 foot 6 inches beyond the 

 head, corresponding to that more developed prominence which has received the name of 

 'third trochanter' in Iguanodon and Scelidosaurus. There is also evidence of a 

 longitudinal ridge (d) continued from the back part of the trochanter, about 9 inches 

 down the shaft, inclining toward the middle of the hinder surface. 



The popliteal cavity (e) is moderately concave, chiefly transversely through the 

 backward production of the outer condyle (g). This is of less breadth posteriorly than 

 the inner condyle (/) but is more convex as well as more prominent. The outward 

 extension of the femur beyond this prominence is somewhat unusual. 



§ 15. Tibia. — This bone is represented by its proximal end and three fourths of the 

 shaft (PI. XXI, figs. 3 — 6). The shaft is more slender in proportion to the head than in 

 Hylceo- 1 or Scelido-~ saurus, and yields a full subelliptic section (ib., fig. 6). Part of the 



1 Pal. Monogr., 'Wealden Reptilia,' vol. for 185G {Ilylceosaurus), p. ] 7, pi. vii. 



2 Pal. Monogr., ' Liassic Diuosauria,' vol. for 1861 (Scelidosaurus), p. 16, pi. x. 



