

/ • /.'. Sabin. 



. 



km 



Fig. .">. — Injected specimen of the anterior cardinal \<'in and its branches 

 in an embryo pig measuring 11. mm. in its greatest diameter. Magnified 

 about 33 times. This Is the stage at which the lymphatic vessels begin to 

 develop. The vessels were injected with India ink through the umbilical 

 artery. D. C. = duct of Cuvier; V. c p. vena cerebralis posterior; F. a. v. 

 = primitive vena ulnaris; V. 5 Hftn segmental vein. 



