i 4 4 - ANIMAL LIFE PAST AND PRESENT. 



have been caused by the extremity of the tail of one 

 of these creatures as it walked across the soft mud 

 now consolidated into stone. > The impression of the 

 wings shows that these consisted of a soft leathery 

 membrane, probably something like that of the wing 

 of a bat; and it is quite evident that there were no 

 feathers either on the body or the wings. The body, 

 like the wings, was, indeed, in all probability entirely 

 naked; and this circumstance militates against the 

 suggestion that the Flying Dragons were warm-blooded 

 creatures, since a protection of either fur or feathers is 

 found necessary in the case of birds and bats to main- 

 tain their high temperature. The Khamphorhynchs 

 occur not only in the Lithographic limestone, which 

 is situated near the top of the great Oolitic system 

 the system underlying that of the Chalk but are also 

 found in the older Lias. Another group, also found 

 in the Lias, are characterised by their short skulls 

 and the superiority in size of the front over the hinder 

 teeth, in consequence of which they are known as 

 Dimorphodonts. 



Perhaps, however, the most remarkable forms found 

 in the whole group are the toothless types, or Pterano- 

 donts, of which a skull is shown in Fig 45. In these 

 creatures teeth were totally wanting, and the jaws 

 were probably sheathed in horn, like those of tortoises, 

 while the hinder or occipital region of the skull was 

 produced into an enormous flattened spine, which also 

 recalls a feature found in the tortoises (see Fig. 31, 

 page 107). Whereas most of the forms we have hitherto 



