321 



anterior true molar* : (lie crown of the fourth molar if visible in iu formative alveolus, and 

 the prrmolar is exposed above the deciduou* molar which it was about to displace. Tin- con- 

 ititurut bonn are numbered according to the TABLE or SYNONYM*. 



Purchased 



1727. The disarticulated bones of the head of a young Kangaroo (Macropiis major). 



They are numbered on coloured label* answering to the TABLB or SYNONYMS. 



The cite of the jaw* indicate* that the animal had died at the period when the young Kan- 

 garoo ha* begun to quit the pouch, but still return* to it for occasional refuge. 



The teeth in use are, i }, m 5 ; or one incisor and two molar* on each cide of both 

 upper and lower jaw*. The incisors are i I , or the first of the three in the upper jaw, and 

 the single long procumbent incisor in the lower jaw. The molar* are the deciduoiu erie*. 

 and aniwer to the hut two deciduou* molars in the Hog and Dog ; vis. d 3 and d 4. The 

 crown of the second incisor i* visible in the premaxillary bone, and a foramen exposes the 

 germ of the third incisor. The crown of the first permanent true molar, and the germ of 

 that of the second, may be discerned in their formative alveoli. 



Prftentfd by Prof. 0rr, F.R.S. 



1728. The skull of a young Kangaroo (Macropiu major). 



All the incisor* are permanent : the outer one* above are nearly in place. The deciduou* 

 molar*, d 1 and d '2, are in titu, together with the first true molar, M 1 , in both jaw* : the 

 germ of the premolar, which after the fall of the deciduous molar* become* the first of the 

 permanent eerie*, i* exposed in the cavity of reserve, on the left tide of both up|>cr and lower 

 jaw*. 



Pretenfed by Mr. Mornay, 1809. 



1729. The mutilated skull of a young Kangaroo (.\fatroptu major), exhibiting the 

 permanent premolar teeth in their formative alveoli or cavities of reserve. 



The molar teeth I'M tit* are the two deciduous molar*, d 1 and d 1, and the first true molar, 

 ) , on each side of both jaw*. The premolar, which become* the first or foremost of the 

 permanent series, is still incomplete and in its cavity of reserve : this is laid open on the left 

 ide of the upper and the right side of the under jaw. The element* of the occipital bone 

 being still un-united, the luperoccipital and interparietal have been removed, showing the 

 commencing development of the bony tentorium from the parietals. The nasal bone* are 

 removed, showing the coalesced prefrontal*. The left tympanic i* also removed, in order to 

 how the continuation of the tympanic cavity into the air-cell of the lygoma, by the pneu- 

 matic foramen at the back part of that proce**. 



llunttria* 



1730. The skull of a Kangaroo (Macropiu major), showing the next stage of den- 

 tition, which consists in the acquisition of an additional (the second true) 



2r 



