FOSSIL MAMMALIA FROM THE STONESFIELP SLATE. 419 



of the third tooth, which in turn has all the characteristics of 

 a molar/^ Osborn concludes that the formula may be pro- 

 visionally written i. 4, c. 1, pm. 2, m. 5. In assigning this 

 formula to Phascolotheriura I entirely agree with Professor 

 Osborn, and can only say that the difference between the first 

 two grinders and the succeeding molars is perhaps even more 

 marked than he has described. 



The Oxford Museum specimen; a left ramus, seen 

 from the inside (PI. 26, fig. 8). 



This specimen has been figured in outline by Phillips (24) 

 and mentioned by Osborn (15). Mr. Lyddeker, in the British 

 Museum catalogue (12), erroneously referred it to the genus 

 Amphilestes. 



Behind are four molars in very good preservation, showing 

 the marked cingulum rising in the two internal points charac- 

 teristic of the genus; in front and behind the cingulum forms 

 small, sharp cusps. I have lately exposed from the matrix an 

 entire incisor, and as far as possible the sockets of the other 

 teeth which are missing. This jaw is, therefore, now of some 

 use in making out the dental formula. Posteriorly we have 

 the four molars already mentioned, and immediately in front 

 of these are two sockets, presumably belonging to the first 

 molar. Then come two pairs of sockets, of which the anterior is 

 much the smallest, in which were the two premolars. In front 

 of these, again, is the large alveolus of the canine, preceded 

 by two sockets for two incisors. Next comes the incisor 

 recently brought to light, which in shape is stouter at the base, 

 more closely resembling the incisors of Thylacinus than seem 

 to do those of the type specimen. Beyond this tooth the jaw 

 is slightly damaged; the first incisor has probably been broken 

 away. The dental formula of this jaw would then agree with 

 that given by Osborn for the type specimen, and adopted here. 



Mr. Parker's specimen; a portion of the right ramus 

 with the inner surface exposed (PI. 26, fig. 9). 



This, the third and last specimen of Phascolotherium, is the 



