202 



THE BATH OOLITE PERIOD. 



CHAP. 



mesial hollow dividing- the buttress. Into this the posterior zyga- 

 pophysial process fits by the prominent roof-like base of the neural 

 spine and the grooved triangular buttress below, making a double 

 adaptation (see Diagram LIX. figs. 3, 4, 5). The edges of the 



Diagram LIX. Megalosaurus. One-tenth of natural size. 



i. Sacrum, seen on the right side. Oxford Museum. 2. Vertebra figured by 



Dr. Buckland as caudal, seen on the right side. 3. Vertebra anterior dorsal, 



seen on the right side. 4. The same, seen on the anterior face. 5. The posterior 

 zygapophysis of the same. 6. Rib middle dorsal, thirty -four inches. 7. Rib 



first or second dorsal, eight inches long. 



The arrow in each case is represented as flying from the head. 



zygapophyses are connected by a sort of vertical crest parallel 

 to the axis of the vertebra. 



The upper posterior zygapophysial articulating faces, which look 

 downward and outward, are but little convex, and inclined to each 

 other about 135 ; the lower posterior faces (see Diagram LIX. 

 fig. 5), which look upward and inward, are inclined to each other 

 about 45. 



The neural spine, three inches broad, is broken off at 3-5 inches 

 from the base. It was probably fully of the length given in Pro- 

 fessor Owen's lithograph (fourteen inches), for the vertebrae shewn 

 in that drawing are not quite so large as ours. The spines are 



