ROOM III. SPINAL COLUMN OF THE HYL.EOSAURUS. 323 



previously described, but the quantity collected was very 

 considerable ; there was, also, a large number of mutilated 

 ribs, and of fragments of bones too imperfect to be deci- 

 phered. The following are worthy of notice : 



A perfect Scapula (Lign. 69, fig. 1), eighteen inches long, 

 and the proximal or pectoral end of the corresponding bone. 



One Humerus, sixteen inches long ; this bone is perfect, and 

 the radio-ulnar or distal articulation beautifully displayed 

 (Lign. 69, fig. 2.). 



A phalangeal bone of very abbreviated proportions. 



Ribs : some are perfect, but several specimens show the 

 well developed neck and tubercle for articulation with the 

 vertebra, 



A very peculiar character in some of these costal frag- 

 ments, is the enormous expansion of the outer border of 

 the rib, so as to constitute a wide plate, approaching to that 

 of the Chelonian reptiles. This anomalous character may 

 possibly have relation to the largely developed dermal ap- 

 pendages of the dorsal region. 



SPINAL COLUMN OP THE HYLJEOSAURUS. Wall-case B. 

 A third example of this saurian was brought to light in a 

 quarry in Tilgate Forest, but a short time before I left 

 Brighton, in the autumn of 1837. This fossil, like the 

 former, fell into the hands of the parish labourers, who were 

 unacquainted with the increased value of carefully extracted 

 specimens. From the connected state of the vertebrae, even 

 when first seen by me, it is certain that a much larger portion 

 of the skeleton was imbedded in the rock, and might have 

 been obtained with due care. 



This most valuable specimen is placed immediately above 

 that first described. It consists of three distinct portions of 

 the spinal column, comprising twenty-five caudal vertebra?, 

 which bear three distinct and peculiar modifications of the 

 ha3mapophyses. 



Along each side of the vertebral column, there are several 

 dermal bones of a circular or discoidal form, varying from one 

 to three inches in diameter. There are likewise the bases of some 

 very large angular dermal spines, analogous to those described 

 in the first specimen (ante, Lign. 66). Thus while the sca- 

 pulae and ribs prove the generic relations between the first 

 and second specimens, the dermal bones and vertebral column 



