84 
FOSSIL JAWS OF MACROPODIDM, 
Succession of teeth. 
The two anterior true molars are still but little affected by 
wear when p. 4 has reached a forward stage of incubation, and in 
the lower jaw p. 3 is still in position and little worn when the 
hind lobe of m. 2 is well advanced and its fore lobe nearly in use. 
The upper premolar and last molar are half worn down simultane- 
ously, m. 1 being at the same time reduced almost to a shell. 
Prom these data it would seem that the anterior true molars 
rapidly develop in the young jaw; that the upper premolar 
probably rises simultaneously with m. 4 , and that it persists to an 
advanced period of life. 
The immediate affinities of Palorchestes are with Halmaturus 
rather than with Macropus. 
Exa 71 iples — ? i me. 
Maxillary. — A cast of the palato-maxillary region of the skull 
with all the cheek-teeth; original in the Australian Museum. Like 
the cast, which has the same history and is numbered M. 2573 in 
the British Museum Catalogue, it is inscribed " Macropus," and 
is without any doubt from the same mould — Portion of a right 
maxilla of a young example with m. 1 , m. 2 and the crypt of p. 4 
— An isolated m. 4 , an isolated m. 3 , and an isolated m. 2 . 
Mandibular. — Portion of a left ramus, with p. 4 , m. 1 , m. 2 , 
aged, vascular foramen distinct — A left ramus with m. 3 perfect 
and remains of m. 2 and m. 1 , adult, vascular foramen distinct — - 
Part of an isolated m. 4 — Associated rami of a young mandible 
with i. 1 , p. 3 , mp. 4 , m. 2 , from the Peak Downs. 
Palorchestes parvus, n.s. 
Constantly smaller than P. azael, the cheek teeth measuring- 
less than 10O0. Upper fourth premolar with a distinct anterior 
talon, lobe of the lower fourth premolar deeply emarginated on 
the posterior surface of the inner side, its area of abrasion narrow, 
angular, and extended transversely. 
