270 PALEONTOLOGY. 



from the rest of the dentition by a pair of upper and a pair 

 of lower canines, as well contrasted by their superiority of 

 size as in Galesaurus. Instead, however, of these canines 

 being immediately followed by small molar teeth, there was 

 a toothless space extending at least as far as the upper jaw 

 has been preserved on the fossil under description ; and this 

 space equals at least twice the breadth of the crown of the 

 upper canine. Other specimens are required to complete our 

 knowledge of the dentition. 



The relative positions of the incisors and canines were 

 nearly the same as in Galecynus; the crowns of the lower 

 canines were perhaps more completely concealed when the 

 mouth was shut. The nostril is single, terminal, of a trans- 

 versely oval shape, with the plane of its outlet inclined from 

 above downward and forward. The aperture is bounded by 

 the premaxillaries (fig. 3, ^^) below and at the sides, and by 

 the nasals (ib. 15) above. The extremity of the upper jaw, 

 pierced by the nostril, is slightly expanded, as in the Teleosaur, 

 but in a less degree than in the Gavial. 



Order VI. — Pterosauria. 



Char. — Pectoral members, by the elongation of the anti- 

 brachium and fifth digit, adapted for flight. Vertebrae 

 proccelian ; those of the neck very large, those of the 

 pelvis small. Most of the bones pneumatic. Head large ; 

 jaws long, and armed with teeth. 



The species' of this order of reptiles are extinct, and peculiar 

 to the mezozoic period. Although some members of the pre- 

 ceding order resembled birds in the shape or the edentulous 

 state of the mouth, those of the present order make a closer 

 approach to the feathered class in the texture and pneumatic 

 character of most of the bones, and in the development of the 

 pectoral limbs into organs of flight (fig. 97). This is due to 



