Charles F. W. McClure 375 
As a general rule the pulmonary veins of marsupials probably pre- 
sent as wide a range in their method of termination as these veins do 
in the higher mammals. They may open into the auricle by means 
of a V. pulmonalis communis as in Didelphys, close together as in 
Petrogale (Parsons, 96), or in separate groups as in Thylacinus and the 
wombat (Rise, go). Owen, 66, as opposed to Rése, states that in the 
wombat they may open close together or by a single trunk. 
4. The Coronary Veins.—The coronary veins of Didelphys consist 
of a dorsal (posterior) and a ventral (anterior) group. The dorsal 
group consists of one large and several small veins, which, for the most 
part, lie upon the surface of the left ventricle and open into the left 
precava near its point of termination in the right auricle. The ventral 
group also consists of one large and several small veins. The small 
veins open directly into the right 
auricle. The large vein (V. cordis 
magna, V. c. m. in Text Fig. I), 
which lies in the ventral (ante- 
rior) interventricular furrow, 
does not, as in most mammals, on 
reaching the auriculoventricular 
groove deviate to the left and open 
into the left precava, but pursues 
a course somewhat similar to that 
of a coronary vein in birds, by 
passing dorsad between the root 
of the pulmonary artery (A. p.) 
and the left auricle and then de- 
viating to the right over the dor- 
sal surfaces of the roots of the 
pulmonary artery (A. p-) and Fie. I. Diagram of vessels at base of heart. 
Didelphys marsupialis. Showing course of V. 
aorta (Ao.) to open into the at- cordis magna. Ventral view. <Ao., aorta; A. 
f h p., pulnonaLy artery; CS., crescentic notch ; 
4 io 2a pre. d., right precava; pre. s., left precava; 
lags of the right pneceyA (pre. RAS right auricle ; RV., right ventricle; V. c. 
Ge as m., V. cordis magna. 
Cunningham was the first, so far as known to the writer, to notice 
the unusual course of this vein in marsupials (Thylacinus), and re- 
garded its peculiarity as one of the two distinctive characters of the 
5In birds (Buteo borealis and Somateria mollissima) the vein in question pursues the 
same course as in Didelphys with the exception that it does not lie dorsal to the root 
of the aorta, as the vein opens further to the left into the sinus common to the open- 
ings of the postcava and the right precava. 
