1893.] MB. M. F. WOODWAED OX MAMMALIAJ? DENTITIOIN-. 463 



lower incisor is present as in Petrogale with a rudimentary suc- 

 cessor, the functional incisor being t„ and shows a distinct indica- 

 tion of its successor in the second dentition (fig. 11, r') ; no trace 

 of ^3 was observed. 



The canine is large and late to calcify, being uncalcified in the 

 largest specimen examined, of which the head measured 83 mm. 



In the diastema between the canine and the Brd premolar, the 

 dental lamina presents numerous small enlargements and irregu- 

 larities, some of which possibly represent the missing premolars. 

 In the lower jaw, however, there is a very distinct vestige of a 

 tooth in the form of an irregular enamel-organ with enamel- 

 epithelium and pulp (fig. 1-i). This, from its proximity to the 3rd 

 premolar, must represent ^?)?2. 



The one functional successioual premolar in the youngest speci- 

 men examined is developed as an enlargement of the dental lamina 

 between pm^ and p»i' (fig. 21), being continuous with the slight 

 downgrowth developed on the inner sides of those teeth (figs. 20 

 and 22). In this respect it differs slightly in origin from that of 

 Petrogale, where it was directly continuous with the enamel-organs 

 themselves, and not with, any internal lamina ; this may be due to the 

 specimen under consideration being older than the Petrogcdc, as even 

 in that form this tooth subsequently takes on this internal position. 



These two slight downgrowths (figs. 20 and 22) may perhaps 

 represent rudimentary permanent teeth, in which case the two 

 functional premolars must both be regarded as belonging to the 

 first dentition. 



In the older specimens the successional premolar subsequently 

 takes on a position internal to the posterior end of irrii^, and loses 

 its connection with pm*, w ith which its connection was at the best 

 very slight. 



In the youngest specimen the 1st molar above and below was 

 just formed, and while the lower one showed no indication of any 

 accessory tooth rudiment, the upper one (fig. 26) had exactly the 

 same relationas seen in Petrogale ; that is, a downgrowth of epithe- 

 loid cells from the dental lamina external to and nearer the gum 

 than the molar itself. This, as I have before pointed out, must be 

 regarded as a vestige of the 1st dentition, and the molar teeth, at 

 any rate the 1st, must be regarded as belonging to the 2nd dentition. 



MaCEOPUS BENXETTII (B,t]TIC01LIs). 



One very badly preserved head. This, when clarified, showed 

 that there were present in the premaxilla 5 incisors, the three func- 

 tional being i\ ^^ and ^^ and the two vestigial ones being i^ and i'. 



The dried skiUl of a very advanced pouch foetus showed that 

 the canine was very large for a Macropus and calcified, and I 

 should think in all probability cuts the gum and is shed, not 

 reabsorbed. The first specimen was too much macerated to make 

 out any detailed tooth relationships, and 1 only mention it here to 

 show iiow constant is the presence of at least two of these 

 vestigial incisors (viz. i'^ and i'). 



