170 MR. MARSHALL ON THE DEVELOPMENT OF THE GREAT ANTERIOR VEINS. 
what is termed a case of “double vena cava superior.” I, 2, 3, 4, 8, 9, 10, 11 and 
e, refer to the same parts as in Plate I. fig. 1. 13. The vagus nerve. 14. Portion of 
the left phrenic nerve resting on the left vena cava superior, d. The cross branch 
at the root of the neck passing across below the place of junction of the subclavian 
and jugular veins, /i. Part of the right vena cava superior, i. A left superior inter- 
costal vein crossing over the descending aorta and acting as a small left azygos vein, 
yj V, /, o and s, are placed on the successive portions of the left vena cava, or persistent 
left primitive vein, which correspond with the successive remains met with in the 
ordinary condition, viz. y, with the subpleural fibrous bands; v, with the vestigial fold 
between the left pulmonary artery and veins ; /, with the lines on the back of the left 
auricle ; o, with the oblique vein ; and s, with the coronary sinus. Into this latter 
there open, g, the great coronary vein, p, a posterior, and m, the middle cardiac vein. 
