LIASSIC CROCODILES. 137 



Teleosaur to dry land, and to the light and slender character of its jaws and teeth 

 with the consequent diminution of the weight of its head. (Crocodilia, PI. 1.) 



Pelvic extremity. —The pelvis of the Teleosaur was attached, as in the Crocodile, 

 to the thickened and expanded transverse processes of two sacral vertebrse. 

 These processes are stronger in the vertical direction, and intercept a relatively 

 smaller and more regularly elliptical space than in the existing Crocodiles ; the 

 anterior one appears not to have been so much expanded in the antero-posterior 

 direction. The iliac bone seems to have been shorter in the antero-posterior 

 diameter, but longer, as measured transversely to the axis of the trunk, and thus 

 to have made a slight approach to its characteristic form in the Bnaliosaurs. 



Both the ischium and pubis are relatively more expanded than in the Gavial. 

 The pelvic extremities are preserved in the Whitby specimen in nearly their true 

 relative positions ; but the right is thrown directly over the left. The femur 

 presents the usual form but is relatively more slender than in the existing Croco- 

 dilians ; it is slightly twisted, and bent in two directions. Its proximal end is 

 expanded, compressed with a regular convex curve, describing a semi-circle ; the 

 trochanter is represented by a ridge which gradually subsides, and is lost upon 

 the surface of the shaft. This is nearly cylindrical at the upper part, but is pro- 

 duced at the anterior or convex side along the distal half in the form of an 

 obtuse ridge. The condyles are very feebly indicated. In the Whitby specimen 

 of 1824, 



The length of the femur is . 



The breadth of proximal end of ditto .... 



The diameter of middle of shaft ..... 



Both the tibia and fibula are subcompressed towards their distal end : the length 

 of each bone is 8 inches. The shaft of the fibula is nearly as thick as that of the 

 tibia. The bones of the leg of the Tehosaurus resemble those of Aelodon in their 

 relative shortness as compared with the femur. In these, and probably in other 

 ancient Crocodiles with biconcave vertebrae and marine habits, the tibia is little 

 more than half the length of the femur ; while in recent Gavials it is two thirds 

 that length. There are five tarsal bones, two in the proximal and three in the 

 distal row, as in the Gavial ; but they are of more equal size ; the two proximal 

 bones being by no means so disproportionately large. All the long bones have 

 distinct medullary cavities, and these are even present in the metatarsals. In the 

 Whitby specimen, 



The length of the middle metatarsal is . . . . . .6 inches. 



The breadth of its proximal end . . . . . .10 lines. 



The breadth of its distal end . . . . . . 6 ,, 



18 



