REPTILES OF THE CHALK. 
149 
a very satisfactory manner ; the researches of that 
philosopher having shown that the posterior caudal 
possess the structure here described, “ Vos 
en chevron n*y est plus articule^ mais soude^ et fait 
corps avec dies.** The situation of this inferior pro- 
cess, presents also another striking proof of the 
identity of the vertebrae before us, with those of 
the Maestricht monitor. In the lizard tribe in 
general, the chevron bone is placed at i\\e junctiori 
of the vertebrae ; and in the monitor, at the poste- 
rior part ; but in the animal of St. Peter’s moun- 
tiiin, it is attached to the middle of the vertebnn, as 
in the specimens before us. 
That the reader may form his own opinion upon 
this interesting subject, Cuvier’s anatomical descrij)- 
tion of the vertebral column of the Maestricht ani- 
mal is here subjoined. The extract is rather long, 
but it will not be deemed irrelevant, when the im- 
portance of extreme accuracy in these researches is 
didy considered. 
“ Toutes ces vertebres, comme cedes des croco- 
diles^ des monitors, des iguanes, et en general de 
la plupart des sauriens et des ophidiens, ont leur 
corps concave en avant et convexe en arriere, ce 
qui les distingue deja notablement de cedes des ce- 
taces, qui I’ont a-peu-pres plane, et bien plus encore 
de cedes des poissons, ou il est creuse des deux cotes 
en cone concave. 
“ Les anterieures ont cette convexite et cette 
concavite beaucoup plus prononc^es que les poste- 
rieures. Quant aux apophyses, leur n ombre etablit 
cinq sortes de ces vertebres. 
“ Les premieres ont une apophyse epineuse 
L d 
