400 



MR. ST. GEORGE MIVART ON THE 



vertebra. It has here mounted more dorsally. The styliform rib-like process is rather 

 longer in this fifth vertebra, but otherwise like that of the fourth. 



The nietapophysis is rather more swollen and prominent ; but the hyperwpo;physis is 

 still more reduced. 



The prezygapophysis projects preaxiaUy beyond the parapophysis to a less degree 

 than is the case in the fourth vertebra. 



The neural sjjine is relatively less than that of the fourth vertebra, but otherwise 

 resembles it, except that the two margins of the preaxial excavation do not stand out 

 preaxially on processes with near so much distinctness. 



The neural a^'ch when viewed from above is still less quadrate than in the fourth 

 vertebra, because the transverse extent of the preaxial end of the fifth vertebra exceeds 

 that of the postaxial part of the same vertebra more than the one exceeds the other in 

 the fourth vertebra. 



The postaxial margin of the neural arch is also much more decidedly and sharply 

 concave. 



The Sixth Vertebra. 



The sixth vertebra, though a larger bone than the fifth, resembles the latter in form 

 and proportions, even more than the fifth vertebra resembles the fourth. Both the 



VENTRAl ASPECT OF SIXTH VERTEBRA (natural size). 

 Fig. 25. 



Letters as in last figures, and in addition c, catapophysis. 



pre- and postaxial surfaces of the centrum agree with those of the fifth vertebra 

 respectively ; and the neural surface only difiers from that of its serial predecessor in 

 being slightly more exposed preaxially. 



The ventral surface exhibits no noticeable difiierences, except that the hypapophysial 

 ridge is stUl more obsolete, and that the postero-inner part of each parapophysis begins 



