Thecodontosaurus and Palseosaurus. 149 



centrum to the summit of the neural spine is X-^ts inch. It is 

 interesting as preserving the chevron-bone in natural articu- 

 lation and for showing that the posterior facet for this bone is 

 twice as wide as the anterior facet. The proportions of the 

 centrum are Crocodilian rather than Saurischian. 



The caudal vertebra in slab 63 Brist. Mus. is liij- inch 

 long. The articular faces of the centrum are about y^^ inch 

 deep anteriorly and posteriorly. The vertebra is posterior in 

 position to no. 17, for the transverse process has become 

 reduced to a tubercle. The height to the summit of the 

 neural spine is lyV inch. (See fig. 3, c.) 



No. 19 Brist. Mus. includes three small caudal vertebrge 

 in which the neural spine is lost. The centrums are each 

 about y'u inch long. The postzygapophyses are received 

 between the prezygapophyses, indicating a vertical movement. 

 The contour between the zygapophyses longitudinally is 



Ilium of Palajosaurus. (Figs. 2 and 3.) 



The iliac bones already referred to which occur in the slab 

 no. 63 are associated with a caudal vertebra, double-headed 

 ribs, proximal end of a tibia, a fragment of fibula, and other 

 remains. The anterior angle of the ilium is small and appears 

 to be imperfect, and the posterior angle is worn. The gently 

 convex superior crest is 3^ inches long as preserved. Its 

 middle part approximates towards the sacrum, owing to the 



Fig-. 2. 



Posterior crest. 



Ischiac process. 



External aspect of left ilium of Paleeosaurus. 

 Brist. Mus. no. 63. ^ nat. size. 



outward reflexion of the anterior angle, which makes the 

 superior contour of the crest of the bone concave in length. 

 The posterior angle of the crest is much more prolonged than 

 the anterior angle, so that one half of the bone is behind the 

 posterior border of the acetabulum. The superior and inferior 

 edges of this process converge, but they are subparallel and 

 Ann. & Mag. N. Hist. Ser. 6. Vol xv. 11 



