323 

 1734. The skull of a female Kangaroo (Macroptu major). 



The anterior half of the but molar, M 4, it estricated from itt alveola* : the pmnoUra are 

 till retained : a portion of the outer alveolar wall hat been removed from the right ramiu, 

 exposing th wcketa of the anterior molara and the dental canal. From the menagerie at 



1735. The cranium of a female Kangaroo (Macroptu major). 



The last (fourth true) molar, m 4, it in place, the premolar* are ihed and their tockeU 

 obliterated. The caharium hat been removed, allowing the termination of the carotid canaU 

 in the back part of the lella tunica ; and the common cretcentic nature at iu fore part, which 

 answer* to the foramina optica and foramina lacera anterior*. The deep cerebellar fotMB in 

 the petrotalt are also worthy of notice. The entocarotid perforate* the intrrtpace between 

 the ali- and bati-tphenoid, grooving mott deeply the former : it converge*, inclining forward* 

 and upwards, toward* iu fellow, and terminate*, teparated by a median bar of bone equal to 

 the diameter of the canal, from iu fellow. 



Presented by Prof. Ovent, F.E.S. 



The four following specimens, from the tame Donor, thow the progrra of development of the molar 

 trie* in the left ramut of the lower jaw of the Macroptu major, and are figured in the Article TBKTH, 

 4 Cyclopedia of Anatomy,' vol. iv. 



1736. The two deciduous molars, <l \. </2, and the first true or permanent molar, m 1, 

 are in place, the crown of the second true molar is seen buried in its socket, 

 and the socket of the third true molar, with the germ of that tooth, is visible. 

 The premolar is artificially exposed in its closed alveolus below the interspace 

 between the two deciduous molars. 



1737. The molar teeth in use are four in number, the second true molar having risen 

 into place without the loss of any of the deciduous molars. Besides the ori- 

 fice of the alveolus of the third molar, a groove is now continued backwards 

 from its posterior part, which leads to a minute foramen opening into the small 

 cell containing the germ of the fourth molar. The deciduous teeth have been 

 pushed forward, as it were, by the rising of the second true molar into place, 

 but without a corresponding advance of the reserve- socket of the premolar, 

 /; 4, the crown of which is now, therefore, directly beneath the second deci- 

 duous molar, >/4. 



1738. In this jaw the grinders in use are four in number, as in the preceding speci- 



2r2 



