﻿MONOGRAPH 



ON THE 



Genus BOTHRIOSPONDYLUS. 



§ 1. BOTHRIOSPONDYLUS FROM THE KlMMERIDGE CLAY. 



Species — Bothriospondylus stiff ossus, Owen (Plates III — V). 



The subjects of the first section of the present Monograph might be deemed to have 

 more interest for the Anatomist, by reason of the singular modification of vertebral 

 structure which they exhibit, than for the Palaeontologist, as affording evidence of an 

 additional specific or generic form to the already known numerous extinct Saurian 

 Reptiles of the Mesozoic formations. 



The vertebra, for example (PI. Ill), which, by the presence of pre-(p) and post-(y) 

 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 vertebras therewith associated show unmistakable 

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

 shows, at c, c', 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 acpom- 

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

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

 of the depressed form of centrum, in another sacral one (PI. IV, 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. Ill, figs. 1 — 4) are given of the vertebral centrum which appears to 

 correspond with that marked 5 in Tab. V of the { Monograph on the Fossil Reptilia of 



c 



