306 George 8. Huntington and Charles Ff. W. McClure. 
and which does not yet join the jugular sac, as far as we can de- 
termine. This lymphatic complex increases in its dimensions 
from before backward. 
An elongated and fenestrated lymphatic vessel, not yet joined 
to the subclavian approach, lies ventral to the left precava and 
the anlage of the left innominate vein, while another isolated lym- 
phatic is found at the jugulo-cephalic junction. None of these 
lymphatic structures communicate with the veins. 
The lymphatic organization of this embryo foreshadows the 
conditions in the adult. 
The innominate cross anastomosis, the establishment of the 
right and left innominate veins and the reduced size of the left 
precava, are well shown in the 25 mm. embryo (fig 66). 
