1274 



CLASS MAMMALIA. 



As a provisional measure this family may be divided into two 

 groups or subfamilies, of which the first may be eventually raised to 

 the rank of a distinct family. The first subfamily, or Phascolo- 

 th'eriince, is referred by Professor Osborn to his Prodidelphia, and 

 is included in the Triconodontidce {infra). The lower true molars 

 consist typically of three main cusps arranged in a line, together 



Fig. 1141. — Inner view of the right ramus of the mandible of Phascolotherium Bucklandi; 

 from the Stonesfield Slate. Twice natural size. The outline figure is natural size. There 

 should be a fourth incisor. (After Owen.) 



with some accessory cusps ; and it would appear that the upper 

 molars were of similar structure. . The lower incisors are separated 

 from one another by intervals. The typical genus Phascolotherium 

 (fig. 1 1 4 1 ), from the Lower Jurassic slate of Stonesfield, in Oxford- 

 shire, has the condyle of the mandible placed very low down ; 

 the lower dental formula is I. 4, C. 1, Pm.-\-M. 7, the canine is 

 separated by a diastema from the first premolar, and the true molars 

 have a well-marked cingulum on the inner side. Amphilestes (fig. 



Fig. 1142. — Reversed inner view of the left ramus of the mandible of Amphilestes Broderipi; 

 from the Stonesfield Slate. Twice natural size. The restoration of the anterior teeth is con- 

 jectural ; and the condyle is placed too high. (After Owen.) 



1 142), from the same deposits, has a more numerous series of 

 cheek-teeth, and a higher mandibular condyle. The exact dental 

 formula is not known, although it may have been the same as in 

 the undermentioned Amblotherium. The mandible from the same 

 beds shown in fig. 1143 has been made the type of the genus 

 Amphitylus ; and according to Professor Osborn has teeth of the 



