4 68 



DISTRIBUTION IN SPACE AND TIME 



be mentioned the following: Pareiasaurus (fig. 1325), a particu- 

 larly clumsy-looking creature some 8 feet long and between 2 and 

 3 feet high ; Cynognathus, with skull and teeth not unlike those of 

 a dog; and Dicynodon, possessing large tusk-like upper canines. 

 The five extinct orders of Reptiles now to be mentioned were 



Fig. 1325. Pareiasaurus (much reduced) 



represented by a large number of forms peculiar to the epoch, 

 and severally adapted to the most various conditions of life, in 

 the sea, on the land, and even in the air. 



Fish -Lizards (Ichthyosauria). These were large rapacious 

 marine forms, something like whales in shape, and with paddle- 

 like limbs (fig. 1326). Judging from their enormous eyes they 



Fig. 1326. Restoration of Fish- Lizard (Ichthyosaurtts), much reduced 



were of nocturnal habit. Another interesting feature was the 

 unsymmetrical tail, with the larger lobe below. The shape of 

 this would facilitate return to the surface after diving (see vol. iii, 

 p. 289). 



Sea- Lizards (Plesiosauria). These also were marine reptiles 

 with large paddles, and the most familiar types (e.g. Plesiosaurus 

 fig. 1327) possessed a long almost swan-like neck. The earlier 

 members of the order appear only to have been semi-aquatic. 



