MESOZOIC TIME — TRIASSIC AND JURASSIC. 



789 



motion ; (5) the vertebrae biconcave, as in Fishes and many Mesozoic 

 Eeptiles; (6) a small pelvis with the bones separate, and no elongation of the 

 pubes. As at the present time the breed of fowls having feathered legs is 

 produced by breeding from fowls having the legs scale-covered, thus sub- 

 stituting feathers for scales, the succession of Birds to Reptiles as regards this 

 particular point is not so strange as, at hrst thought, it might seem to be. 



4. Mammals. — Jurassic Mammals have been found in the Stonesfield 

 slate. Lower Oolyte, and in the Middle Purbeck beds. As in America, the 

 species are probably Marsupials, and Monotremes. Among the species at the 

 former locality are Amphilestes Broderipi (Fig. 1327) and Phascolotherium 



1327-1328. 



Majimals. — Fig. 1327, Amphilestes Broderipi (x 2) ; 132S, Phascolotherium Buclilandi (x 2). Pictet. 



BucMandi (Fig. 1328). The genera Plagiaidax, Microlestes, and Tritylodon 

 are supposed to be Monotreme. 



The following figures of jaw bones of the British species, of natural 

 size, showing the dentition, derived chiefly from Owen's papers, are copied 

 from Osborn's review of the Mesozoic Mammalia. 



1329-1345. 



■i^^aAsjdilayr ^ 



1389 



1340 „ 



1836 - . 



1345 



Fig. 1329, Amphilestes ; 1330, Amphitylus ; 1331, Phascolotherium ; 1332, Triconodon mordax ; 1333, Peramus ; 

 1834, Spalacotherium ; 13.35, Peralestes ; 1836, Peraspalax ; 1337, Leptoeladus ; 133S, Amblotherium ; 

 13.39, Phascolestes ; 1340, Achyrodon ; 1341, Stylodon ; 1342, Athrodon ; 1343, Bolodon ; 1344, Plagiaulax 

 minor; 1345, Stereoffnathus. All natural size. 



