MARSUPIALIA. 209 
Fig. 134. 
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Branches of the abdominal aorta, Kangaroo. 
the termination of this and the two other venous 
trunks in the right auricle has already been 
; noticed. 
_ Respiratory organs—In the condition and 
_ structure of the respiratory organs all the Mar- 
supial species adhere to the Mammalian type ; 
a 
. receives also the coronary vein of the heart: 
/ 
the only tendency to the Ovipara is in the 
_ entireness of the tracheal rings in certain spe- 
cies. In the Phalangista fuliginosa, where I 
counted twenty-nine rings, the first four-and- 
_ twenty were entire; below these they were 
_ divided posteriorly, the interspace growing 
_ wider to the twenty-ninth ring. In the Dasy- 
_urus macrurus the rings of the trachea are 
_ twenty-three in number, and are incomplete or 
rather ununited behind. In the Perameles the 
tracheal rings are divided posteriorly by a fis- 
sure. In no species have I found the trachea 
divided near the larynx into two long bronchiz, 
. 
as in the Rodent genus Helamys, nor convo- 
luted in the chest as in the Edentate Sloth, both 
of which modifications are more striking ap- 
proximations to the oviparous type of structure 
than the entire rings above-mentioned. 
The Jungs present the most simple form in 
the Wombat, in which they consist of a single 
lobe on both the right and left sides, with a 
small lobulus azygos extending from the right 
lung to the interspace between the heart and 
diaphragm. ; 
In the Macropus major I found the right 
lung with two notches on the anterior margin, 
and the left lung undivided. In the Macropus 
Parryi both lungs had one or two notches. 
In another Kangaroo I found the right lung 
divided into four lobes, the left intotwo. The 
azygos lobe is large in consequence of the 
length of the chest in the Kangaroos, and the 
distance of the heart from the diaphragm: it is 
