CROCODILIA. 



219 



numerous slender teeth placed nearly upright in the jaw. The two 

 parietal bones and the two frontal bones are fused together, and the 

 nasals do not extend forwards beyond the basal half of the snout. The 

 supratemporal vacuities are very large, the orbits are also very large and 

 directed laterally, while the antorbital vacuity is a mere remnant or ab- 

 sent. On the palate the suborbital vacuities are large, and the posterior 

 narial opening is pear-shaped, extending forwards a little between the 

 secondary plates of the palatines. The vertebrae resemble those of a 

 modern crocodile, except that the centra are amphiccelous, and that the 



FIG. 136. 



Pelagosaurus typus ; skull from the superior (A), palatal (B), and right lateral 

 (c) aspects, one-half nat. size. L. Jurassic (U. Lias) ; Normandy. E, aper- 

 ture of eustachian canal ; N, posterior nares ; o, orbit ; p, suborbital 

 vacuity; T, supratemporal vacuity; v, venous foramen. (After Owen.) 



centrum of the atlas is not fused with that of the axis. The dorsal 

 armour comprises a symmetrical paired series of broad, overlapping scutes ; 

 the ventral shield consists of a mosaic of small irregular polygonal scutes, 

 united by jagged sutures. These and the external bones of the head, in- 

 cluding the postorbital bar, are marked by a pitted ornamentation. The 

 type species is P. typus, about one metre in length; other forms are at 

 least twice as large as this. 



Teleosaurus and Steneosaurus are armoured marine croco- 

 diles closely related to Pelagosaurus, the former confined to 



