Chap. V.] 



VESSELS OF EMBRYO. 



207 



a paired system of 

 cardinal veins, 

 of which the ante- 

 rior pair collect 

 the blood from the 

 head, and the pos- 

 terior from the 

 body generally 

 (Fig. 90; vc and 

 HC). As these lie 

 at the sides of the* 

 body the blood can 

 only pass to the 

 heart by a trans- 

 verse vessel, the 

 diictus Cuvieri 

 (D). These two 

 pairs of anterior 

 and posterior car- 

 dinal veins are 

 possessed by fishes, 

 and the anterior 



par 

 throughout 



remans 

 the 



AA, Abdominal aorta ; RA. 

 RA, right and left roots of 

 the aorta, connected by 

 the collecting vessels (ss') 

 with the branchial ves- 

 sels Ab; cc', carotids ; s6, 

 subclavian artery; KL, 

 gill clefts ; si, sinus ve- 

 nosns ; A, atrium ; v, ven- 

 tricle ; B, bulbus arterio- 

 su* ; VJH, ompbalo-me?en- 

 tcric veins: Am.omphalo- 

 mesenteric arteries ; ic 

 ic, common iliac arteries; 

 EE.cxternal iliac arteries, 

 A/?,alIantoic arteries ; Acd, 

 caudal artery ; vc, HC, an- 

 terior and posterior cardi- 

 nal veins; s//, subclavian 

 vein ; D, diictus Cuvieri. 

 (After Wiedersheiiu.) 



Pig. 90. -Diagram to explain the Arrange- 

 ment of the Embryonic vascular System. 



