92 
FOSSIL JAWS OF MACROPODID.E, 
assume its full functions with the change of the premolars. In 
the lower the permanent premolar wears down rapidly during the 
earlier part of its career; all its asperities have disappeared 
before the hind lobe of m. 4 is affected by use. Masticatory work 
is afterwards done principally by the posterior grinders, as the 
premolar is but little more reduced in height, though the last molar 
is that of an aged individual. 
Examples — twenty -two. 
Mandibular. — -The associated rami of a mandible with all the 
cheek-teeth perfect, the incisiors and left ascending process 
wanting; adult — An adult left ramus with all the cheek-teeth 
perfect, vascular orifice minute — Alveolar region of a left ramus 
with all the cheek-teeth, several of them imperfect; aged — Two 
right rami with all the cheek-teeth perfect; foramen small; 
adolescent --Cast of a right ramus with all the cheek-teeth but 
p. 4 , some imperfect; vascular orifice moderate; adult — A left 
ramus with all the molars and the fangs of the premolar; foramen 
small; adult — A left ramus with the first three molars well 
preserved; foramen small; adult — A right ramus with part of the 
ascending process and the last three molars; foramen large; aged 
— Cast of a portion of a left ramus with m. 3 , m 4 well preserved; 
the originals of this and 10223 being in the Australian Museum — 
Alveolar portion of a right ramus with the first three "molars and 
fangs of the premolar; foramen small; adult — Fragment of a right 
ramus with the last two molars and the premolar well preserved; 
adult — Fragment of a left ramus with part of m. 4 ; adult — Frag- 
ment of a right ramus with m. 4 (10518); adult — An isolated tooth 
m. 2 (11118); adult — Outer wall of hinder half of a left ramus (A. 
9454). 
Maxillary. — A left maxilla with the jugal process and the teeth 
m. 8 , m. 2 , m. 1 (part) and fangs of p. 4 ; no trace of palatal process 
(10224); adult — A left maxilla with jugal process and the teeth 
m. 2 , m. 3 ; no palatal process (10529); adult — Part of a right 
maxilla with the last three molars; no palatal process (10595); 
