324 



men, but the first milk- molar has been shed, and the third true molar has 

 risen into place. The crown of the premolar has now risen into close contact 

 with that of the second deciduous molar, and has excited absorption of much 

 of its fangs. 



1739. In this jaw the grinders in use are also four in number, but they consist of 

 the premolar, p 4, and the three anterior true molars, both milk-molars having 

 been shed. The crown of the fourth molar may be seen in its alveolus, which 

 is here widely open above. 



The lower jaw of the Macropus laniger in the Palseontological Series also shows four 

 grinding teeth in place, hut these consist of the four true molars, the premolar having been 

 shed. 



1740. The skeleton of Bennett's Kangaroo (Macropus Bennettii). 



The inner condyle of the humerus is perforated. The patella is not ossified. The fibula 

 closely adheres to the lower half of the tibia. The seventh (last) cervical vertebra is pierced 

 by the vertebral artery : 13 vertebrae are dorsal, 6 are lumbar, 2 are sacral, and 22 are cau- 

 dal : all of the latter have haemapophyses, save the first. The neural arches of the lumbar 

 vertebrae have two small perforations near their anterior margin, or towards their upper part, 

 for the passage of vessels, not nerves. Both metapophyses and anapophyses are developed 

 from the posterior dorsal and lumbar vertebrae, in addition to the ordinary transverse pro- 

 cesses or diapophyses. There are four grinders in use on each side of both jaws, which con- 

 sist of the two deciduous molars and the first and second true molars. 



Presented by Jacob Sell, Esq., M.P. 



1 741. The skull of a rather younger individual of the Macropus Bcnnettii, in which 

 the second true molars, m 2, have scarcely come into place. 



Presented by George Bennett, Esq., F.L.S. 



1742. The skull of an older individual of the Macropus Bennettii. 



There are five molar teeth in use on each side of both jaws, the third true molar having 

 come into place without either of the milk-molars having been shed : the germ of the pre- 

 molar is exposed above the second and part of the first milk-molar. The sutures between 

 the exoccipitals and superoccipital remain : those between the exoccipitals and basioccipital 

 are obliterated. 



Hunterian. 



