Fig. 25 Baryonyx walkeri, holotype, BMNH R9951; 10-11" dorsal 
vertebrae. A, D10 neural arch fragment in anterior view; B, D11 in 
(from top downwards) anterior, left lateral, and posterior views. x 0.25. 
of its flat dorsal surface (i.e. at the base of the neural spine) there is 
what we might call a dorsal fenestration. Underneath the transverse 
process there are three ventral fenestrations, one at the apex of each 
fossa — an anterior, a middle, and a posterior — making four 
fenestrations altogether on each side of the vertebra. 
In D4 and DS the three ventral fenestrations only are present. In 
D6 and D7 there is also a dorsal fenestration, more pronounced in the 
A.J. CHARIG AND A.C. MILNER | 
Fig. 26 Baryonyx walkeri, holotype, BMNH R9951; 14" dorsal vertebra 
in (from top downwards) anterior, left lateral, and posterior views. x 
0.25. 
contains supplementary buttresses (see above). In D11 the dorsal 
fenestration is still present but the ventral fossae have not been fully 
prepared. In D14 the posterior (infrapostzygapophysial) fossa is a | | 
deep pocket. 
It is evident throughout the series that, in this specimen at least, 
the vertebral centra and the neural arches had not co-ossified. In 
some vertebrae centra and arches had remained together in their 
proper positions, in others they were still together but relatively 
