KIMMERIDGIAN DINOSAURS. 551 



Order. DINOSAJJRIA. 



Genus — Bothriospondylus. 



Species — Bothriospondi/Ius suffossus, Owen (' Dinosauria,' Plates 61 — 63). 



The subjects of the present section might be deemed to have more interest for the 

 Anatomist, by reason of the singular modilication of vertebral structure which they 

 exhibit, than for the Palseontologist, as affording evidence of an additional specific or 

 generic form to the already known numerous extinct Saurian Re[)tiles of the Mesozoic 

 formations. 



The yertebra, for example (Pi. 61), which, by the presence of pre-(p) and post-(;j') 

 parapophyses with expanded rough syndesmotic articular surfaces, is a sacral one of the 

 Dinosaurian type, presents so singular a degree of depression, or horizontal flattening, of 

 the centrum, as to suggest artificial and posthumous pressure as its cause ; and it is true 

 that some of the lumbar or dorsal vertebrae therewith associated show unmistakable 

 marks of such violence. But, as the side view of the present vertebra, ib., fig. 4, 

 shows, at c, e', there is no such evidence of fracture of the peripheral compact layer of the bone 

 with distortion, causing more or less departure from symmetry in the centrum, as accom- 

 panies every instance of crushing out of shape in the present series of vertebrae (compare 

 figs. 1 and 4, e.g., with fig. 5, in PI. 63). There is also evidence of a transitional assumption 

 of the depressed form of centrum, in another sacral one (PI. 62, figs. 4, 5, 6), which, from 

 having the syndesmosal surface on a single parapophysis {p) on each side, was part of a 

 terminal vertebra of the sacral series. 



Four views (PI. 61, figs. 1 — 4) are given of the vertebral centrum M'hich appears to 

 correspond vpith that marked 5 in ' Dinosauria,' PL 38. In the sacrum of the Hglceo- 

 saurus there figured the vertebra No. 5 offers the greatest breadth and flattening of the 

 under surface, which is also notable for the absence of the longitudinal ridges, parial or 

 single, marking the under surface of the succeeding or preceding centrums. 



The under surface of the present sacral (PI. 61, fig. 1) is less accentuated than the 

 Hylseosaurian one compared with it, and the venous canals are relatively smaller than in 

 it : they also issue irregvdarly, instead of being symmetrically disposed as are the large 

 pair in Ilylcsomurus. The under surface, as shown in the side view (ib., fig. 4, c), is feebly 

 undulate lengthwise, the concave curves being mainly due to the expansion of the articular 

 ends (ib., fig. 3). The under surface of the centrum is as moderately convex across, 

 becoming flat near the free portions of the side of the centrum (ib., figs. 1, 2, 4, c'), 

 and very slightly concave th.'ough the distal expansion of the parapophyses (ib., fig. 1, 

 pp'). But the distinctive peculiarity of the present centrum from the known sacral ones 



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