PLATE 7 



- . 



v.a- 



v.o. 



v.a 



16 



v.c.ct. 



-v.c.p. 



Fig. I 6. Injection of the veins in an embryo pig 28 mm. long, to show the relation of the accessory 



hemiazygos vein to the anterior cardinal vein. 



Fig. 1 7. Dissection of an embryo pig 28 mm. long, to show the prevertebral veins. 

 Fig. 1 8. Dissection of an embryo pig 40 mm. long, to show the prevertebral veins. 



