MAMMALS OF THE MESOZOIC PERIOD 



belonged to small mammals. In Fig. 136 two 

 of these very ancient mammalian jaws are 

 figured. 



Fig. ] 36. — Lower jaws of the ancient Mammals, Dromatherium 

 (upper — Trias), and Dryolestes (lower— Jurassic), mag- 

 nified about 2^ times linear. 



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