1896.] ANATOMY OF PETROGALE XANTHOPUS. 687 
towards the head at their ends; they are small on the 1st and 2nd 
vertebre, but rapidly increase afterwards. 
The anapophyses begin on the last three thoracic vertebre and 
disappear on the last two lumbar. 
Fig. 3. 
1st lumbar vertebra of Petrogale, with hypapophysis (H). 
The Clavicle has the usual single forward curve. The Scapula 
resembles that of Macropus in the absence of any sign of a 
metacromial process ; a small metacromion is, however, found in 
Hypsiprymnus. 
The Humerus is chiefly remarkable in that it shows all or almost 
all the centres of ossification; they consist of the following :— 
1, head; 2, greater tuberosity ; 3, lesser tuberosity (quite distinct) ; 
4,-shaft; 5, internal condyle; 6, trochlea and capitellum ; 
7, external condyle. The centre for the internal condyle takes no 
part in the bridge of bone enclosing the supra-condylar foramen. 
The Radius and Ulna show all the epiphyses, but that for the 
upper end of the radius is nearly united to the shaft. ‘he upper 
epiphysis of the ulna merely forms a cap to the olecranon. 
The Carpal bones correspond to Owen’s description. 
In the Pelvis the three parts of the os innominatum are completely 
fused, but there is an epiphysis on the crest of the ilium and on 
the tuberosity of the ischium, the latter stretching along as far as 
the subpubic bone, with which in more adult animals it coalesces ; 
there is also a slight ossific deposit in the centre of the pubic 
symphysis: No special centre is seen for the origin of the rectus 
femoris. 
The Femur shows the following epiphyses:—1, head ; 2, great 
trochanter ; 3, upper part of lesser trochanter ; 4, shaft; 5, lower 
extremity. The epiphyses for the head and great trochanter meet 
on the upper surface of the neck. The outer side of the posterior 
part of the external condyle is lipped and forms a groove for the 
reception of the elevation on the posterior part of the head of the 
fibula during extreme flexion of the knee-joint. The Patella is 
almost entirely cartilaginous, but a small bony deposit is seen in 
the centre. The Z%bia shows the following centres :—1, head ; 
2, upper part of cnemial crest where the ligamentum patelle is 
attached ; 3, shaft ; 4, lower extremity. In studying the ossifi- 
