384 Venous System of Didelphys Marsupialis 
The general character of the azygos veins of marsupials other than 
Didelphys has been described by a number of investigators as indicated 
below. 
Marsupials in which Two Azygos Veins are Present which Open into 
the Right and Left Precaval Veins, Respectively. 
Family—Macropopip&. 
Macropus (spec.?) (OWEN, 66); Halmaturus bennetti (left azygos longer, 
BEDDARD, 95): Petrogale (spec.7) (right azygos longer, MCCLURE). 
Family—PHALANGERID®. 
Left azygos longer in Phascolarctos cinereus, Phascolomys wombat, Cuseus, 
Phalangista and Belideus!? (FORBES, 81). 
Marsupials in which a single azygos vein is present on the right side. 
Family—MAacropopipm. 
Petrogale xanthopus (PARSONS, 96); Petrogale penicillata, Macropus rufus 
and Dendrolagus bennetti (BEDDARD, 95). 
Family—DasyurD&. 
Thylacinus cynocephalus (CUNNINGHAM, 82). 
Marsupials in which a single azygos vein is present on the left side. 
Family-—PHALANGERID. 
Phalangista maculata and Phalangista vulpina (CUNNINGHAM, 82); Phalan- 
gista vulpina (CUNNINGHAM, 82) and Phascolarctos fuscus (MARTIN, 36). 
DASYURID&. 
Dasyurus viverrinus (CUNNINGHAM, 82, and BENDARD, 95); Phascogale calura 
(CUNNINGHAM, 82), 
Family 
Family—DIDeLPHyIp2&. 
Didelphys cancrivora and azare (BEDDARD, g5) and Didelphys (virginiana) 
marsupialis (MCCLURE). 
It is evident from the foregoing table that, with the exception of 
Thylacinus and Halmaturus, a right azygos vein prevails in the 
Macropodide and a left in the Phalangeride, Dasyuride and Didel- 
phyide. 
Beddard, 95, states that he found considerable variation among sev- 
eral individuals of Halmaturus, and the writer is inclined to believe 
that a single azygos vein is the rule in marsupials and that when two 
are present the case may be regarded as a variation. 
127t is difficult to reconcile Forbes’ two statements that in Belidews there is only 
one precava and that the azygos veins in the same animal open into the right and left 
precaval veins, respectively. 
