SECT. XII 



PHYLUM CHORDATA 



413 



union of a pair of frontals in front with a pair of parietals 

 behind. Over the olfactory capsules are a pair of triangular 

 nasals (NA), and applied to their ventral surfaces small 



O W.Q 



""*. "^ ^Js S-'S 



flrfHilgf 

 Ils<icc1^i 



-s-s -Si-ssi* 



paired vomers (VO). On the ventral surface of the skull 

 is a large T-shaped parasphenoid (PA. SPff}, its stem 

 underlying the base of the cranium, while its two arms ex- 

 tend outwards beneath the auditory capsules. 



