EXPLANATION OF PLATE XX. 



Vertebras of Pythonomorpha, one-half natural size : species, Platecarpus ictericus and Platecarpus coryph&ua 

 Fig. 1. Platccarpus ictericus, median dorsal vertebra : a, from behind ; b, from below ; c, from front. 

 Figs. 2-3. Platccarpus ictericus, lumbar vertebra: a, from behind ; b, from below. These vertebras were 



found lying on their sides, and the form of the articular surfaces is slightly altered by 



pressure. 

 Fig. 3. Posterior lumbar vertebra : a, from before ; b, from below; c, from behind. 



4. Platccarpus coryphccus, axis and third vertebra: a, from the-side; b, from below; c, from behind. 



5. Three cervical and two dorsal vertebras : b, c, d, and e, views from side, below, behind, and above, 



respectively ; g, h, i, I:, and 7, similar views of another ; m, n, side and front views of an ante- 

 rior dorsal. 



C. A posterior cervical from behind. 



7. Posterior dorsal vertebra, : a, from below ; b, from above. 



