PRIMITIVE BLOOD VASCULAR SYSTEM 



273 



/L ISp.G. 



A .v.c.v. 



Fig. 268. — A , The development of the vertebral artery in a rabbit embryo of twelve days (Hochstetter 

 from McMurrich). /// AB to VI AB, branchial arch vessels; Ap, pulmonary artery; A.v.c.b. and 

 A.v.c.v., cephalic and cervical portions of vertebral artery; A.s., subclavian artery; C.d. and C.v., in- 

 ternal and external carotid arteries. I.Sp.C, spinal ganglion. B, Arterial system of an embryo of 

 10 mm. (His). Ic, internal carotid; P, pulmonary artery; Ve, vertebral artery; III to VI, persistent 

 aortic arches. 

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