2 FOSSIL REPTILIA OF THE 



cealed some joint, process, or other light-giving or characteristic part of the frame- 

 work. In the course of our operations it soon became evident that the whole 

 vertebral column, in a series of consecutive and but slightly disturbed and mostly 

 coarticulated segments, from the axis to the thirty-fourth caudal vertebrae inclusive, 

 had been raised from their place of deposit; all the parts, save the centrum and 

 a small and low coalesced neural arch, having ceased to be developed, in the 

 terminal caudal vertebrae, the last of which in the recovered series was reduced to 

 dimensions so small as to indicate that but very few remained to complete the tail of 

 the Scelidosaur. The first vertebra of the neck was adherent to the back part of the 

 skull described in the monograph of the Society's Volume for 1859, issued in 1861. 



Vertebral Column. Tabs. I — IX. 



In the series of Liassic masses following that which included the skull the 

 first four contain twenty vertebrae, extending from the axis to the mass including 

 the sacrum, and clearly consecutive save at one part of the neck. 



The back part of the Liassic mass containing the skull of the Scelidosaur 

 includes the atlas vertebra in connection with the occiput, and surmounted by a 

 pair of dermal bones (Tab. I, fig. 1). The block which fits to the fractured surface 

 including the body and the neurapophyses of the atlas contains the axis and third 

 cervical vertebra (ib., fig. 2). The next piece contained one nearly entire cervical 

 vertebra (ib., figs. 3 and 4) and part of a second vertebra. The third, larger, piece 

 contains ten cparticulated vertebrae (Tabs. II and III), but the continuity of the 

 fore part of this mass with the last mentioned cannot be clearly made out. The 

 fourth block fits to that containing the ten dorsals, and includes the five consecutive 

 vertebrae with part of a sixth (Tab. IV). The block which contains the sacrum, 

 has also two vertebrae in advance of it (Tab. VI), part of the first of which lies in 

 the preceding block. 



Thus, we have evidence of at least twenty-two "true" vertebrae; but there 

 may have been one or two vertebrae from the region of the neck which have not 

 been recovered. The vertebra attached to the first sacral seems not to have sup- 

 ported ribs ; the one in front of it has a pair of long, freely articulated ribs, and may 

 be reckoned the last dorsal. Including this, there may be assigned sixteen vertebrae 

 to the dorsal series, if we include therein the ten vertebrae in Tab. II, leaving 

 six or seven to the cervical series. The lumbar series is thus reduced to one 

 vertebra. The sacrum includes four vertebrae. Of the caudal series thirty-five 

 vertebrae are preserved, in five consecutively fitting blocks of matrix, leaving parts 

 of two terminal ones, so small and simple as to show that very few are wanting 

 in the present fossil skeleton. 



