AMPHITHEEIID^. 271 



pi. ii. (under the name of DidelpTiis) ; and also by Owen 

 in the ' Trans. Geol. Soc' ser. 2, vol. vi. pi. yI. fig. 2, in 

 his ' Odontography,' pi. xcix. fig. 4, • and also in his 

 ' Mesozoic Mammalia ' (Mon. Pal. Soc), pi. i. figs. 26, 2Qa. 

 Presented hy W. J. Broderip, Esq. 



Genus AMPHILESTES, Owen \ 



Distinguished from Phascolotlierium by the larger number of 

 lower cheek-teeth, and by at least some of the premolars being 

 simpler than the true molars; in the type species (fig. 41) the 

 cingulum of the tricuspidate true molars encircles the crown, and 

 has niinute fore-and-aft cusps ; the mandibular condyle is 

 apparently sessile and placed on the level of the molars. In the 

 type specimen 2 (fig. 41) there are nine teeth remaining (the crown 



Fig. 41. 



Amphilestes broderipi, Owen.^ — Reversed inner view of the left ramus of the 

 mandible ; from the Stonesfield Slate, f . The restoration of the anterior 

 teeth is conjectural ; and the condyle is placed too high. (From Owen's 

 ' Palaeontology ' ^.) 



of the sixth from the posterior end broken off), of which the first two 

 are clearly premolars ; the third tooth may possibly be a milk-molar, 

 and it is not certain that there may not be an additional molar in 

 its alveolus behind the ninth tooth. 



^ Encyclopaedia Britannica, 8th ed. vol. xvii. p. 157 (1859). In his ' Meso- 

 zoic Mammalia ' (Mon. Pal. Soc.) Owen provisionally included the type species 

 in Aowphitherium, but the observations of Osborn (kindly cominunicated in MS. 

 to the writer) apparently indicate its right to distinction. 



^ Compare Owen's ' Odontography,' pi. xcix. fig. 3. Owen regarded the 

 lower dental formula as 1. 73, C. t, Pm. -, M. - ; but it is quite probable that 



O i D b 



there may have been four incisors, which would reduce the premolars to five ; 

 while, if the specimen be adult, the seventh tooth from the end might be a true 

 molar, in which case there would be only four premolars ; and there may have 

 been a diastema behind the canine. 



^ Wrongly given in that work (fig. 112) and in the ' Encyclopaedia Britannica,' 

 op. cit., as Amphithcrium prevosti, and so reproduced in several later works; 

 it is really reduced from pi. vi. of the ' Trans. Geol. Soc' ser. 2, vol. vi. pi. vi. 

 fig. 1, and pi. xcix. fig. 3 of Owen's ' Odontography.' 



