no 



THE STUDY OF SIX AND TEN MILLIMETER PIG EMBRYOS 



subcardinals lie along the median surfaces of the mesonephroi, more ventrad 

 than the posterior cardinals with which they are connected at either end. There 



A. car. V. card. 



Meten. j n t. ant. Ph. R 2 



Ph. 



Ph. R3 



Mesen 



Ch. d. 



Ao. desc. 



ed. sp. 



V. card.post Aa. mes. Mes. 



FIG. 99. Reconstruction of 7.8 mm. pig embryo showing veins and aortic arches from the left side 

 (Thyng). X 15. Ao. desc., descending aorta; Ao. 11., ventral aorta; A. car. int., internal carotid 

 artery; Aa. mes., mesonephric arteries; A. pul., pulmonary artery; At. d., right atrium; D. v., ductus 

 venosus; Ph. P. i, 2, 3, 4, pharyngeal pouches; S. v., sinus venosus; Th. med., thryeoid gland; V. card, 

 ant., anterior cardinal vein; V. card. com. d., right common cardinal vein; V. card. com. s., left common 

 cardinal vein; V. card, post., posterior cardinal vein; V. hep. com., common hepatic vein; V. is., inter- 

 segmental vein; V. ling-fac., linguo-facial vein; V. oph., ophthalmic vein; V. p., portal vein; V. scar A. 

 d., right subcardinal vein; V. scl. d., right subclavian vein; V. umb. d., right umbilical vein; Ven. d., 

 right ventricle. 



is a transverse capillary anastomosis between them, cranial and caudal to the 

 permanent trunk of the vitelline artery. The right subcardinal is connected 

 with the liver sinusoids through a small vein which develops in the mesenchyme 



