MUEiENOSAUEIIS. 



10^ 



ventral face by rounded ridges, the posterior ends of which in the anterior caudals, and 

 both the anterior and posterior ends in the middle and the posterior caudals, are trun- 

 cated by oblique facets {c.f.) for union with the chevrons ; when both anterior and 

 posterior facets are present, the latter are usually the larger (text-figs. 57—59, c.f.). 

 At the posterior end of the caudal region (text-fig. 58) the centra become reduced in 

 size very rapidly ; the actual terminal vertebrae are not known in this genus. In the 

 anterior part of the caudal region the neural arches are not well known, but it appears 

 that they possessed well-developed zygapophyses and comparatively high laterally com- 

 pressed neural spines. Further back beyond the middle of the tail (text-figs. 58, 59) the 



Text-fig. o8. 



Posterior caudal vertebrae o£ Murcen^isaur'as platydis : A, from below ; B, from front ; 



C, from right side. (E. 2425, f nat. size.) 



c.f., facets for chevrons ; c.r., caudal ribs ; n.a., neural arch. 



arch becomes smaller and stouter, bearing a short thick neural spine («.s., n.a.) ter- 

 minating above in a surface for cartilage ; in this region the zygapophyses have 

 disappeared, or are represented only by slight rugosities. Further back still the arch 

 is more massive and encloses a very small neural canal. The spine is very short and 

 thick, and is almost rectangular in section ; it slopes a little backwards and terminates 

 above in a large, slightly concave surface for a cap of cartilage. There is no trace of 



