DIDELPHYIK^. 285 



27823. Hinder part of the right ramus of the mandible, containing 

 the three true molars ; from the Lower Miocene (Upper 

 Oligocene) of Cournon (Puy-de-D6me), France. The 

 length of the space occupied by the three teeth is 0,007, 

 and the specimen apparently agrees precisely with the 

 type mandible figured by Gervais in the ' Zool. et Pal. 

 Francaises/ pi. xlv. fig. 2. 



Croizet Collection. PurcJiased, 1848. 



Didelphys exilis, Gervais \ 



Syn. (?) DideljyJiys le7nanensis, Pomel ^. 

 Peratherium exile, Gervais ^. 



Considerable confusion has existed in regard to this species owing 

 to the figure of the type specimen (No. 27806) given by Gervais 

 being stated to be enlarged, whereas it is really almost of the natural 

 size. 



The species is nearly of the size of D. affinis and D. arvernensis ; 

 in the type mandible (No. 27806) the length of the series of cheek- 

 teeth is 0,013 (not 0,009 as stated by Gervais), pm. 1 is of consider- 

 able size and separated by an interval from pm. 3, which is longer 

 than pm. 4. The lower canine is directed nearly vertically ; the 

 lower true molars increase in length from the first to the fourth, 

 and have their anterior cusp equal in height to the hinder outer 

 cusp ; and the mandibular ramus is deep. 

 Hah. Europe (France). 



27806. The nearly entire right ramus of the mandible, containing 

 (Fig.) the canine and cheek-teeth ; from the Lower Miocene 

 (Upper Oligocene) of Cournon (Puy-de-D6me), France. 

 This specimen is the type, and is figured by Gervais in 

 the 'Zool. et Pal. Francaises,' 2nd ed. p. 264, fig. 34, the 

 figure being very slightly above the natural size. 



Croizet Collection. PurcJiased, 1848. 



Didelphys lemanensis (Filhol ^). 

 Syn, AmpMperatherium lemanense^ Filhol ^. 



The length of the lower series of cheek-teeth is 0,012, and that of 

 the four true molars 0,007 : pm. 1 is small, pm. 3 and pm. 4 are 



^ Zool. et Pal. Fran9aises, 2nd ed. p. 264 (1859). — Peratherium. 



2 Catalogue Methodique, p. 118 (1853). ^ Loc. cit. 



4 Ann. Sci. Geol. vol. x. art. 3, p. 201 (1879). —Ampkiperathcruim. The 

 specific name is preoccupied by D. lemanensis, Pomel ; but as the hitter appears 

 to be a synonym of D. exilis it seems unadvisable to make a change. 



^ Loc. cit. 



