TRANSVERSE SECTIONS OF EMBRYO OF 12 MM. 



265 



designated in the adult as the posterior communicating branch, by which the end 

 of the carotid proper anastomoses with the basilar artery. At the side of the fore- 

 brain appears a blood-vessel, Card.L, which might be called the lateral cardinal. 

 It is a branch of the main cardinal stem and passes over the side of the fore-brain 



Ec.gl. AT. 7, 8. Cin. Epen. Raph. Ven.IV. 



A.bas. 



Pia. 



A. car. 



Ven.III. 



Card.L. 



Arach. 



FIG. 190. PORTION OF FIGURE 189 MORE HIGHLY MAGNIFIED. 



A.bas, Basilar artery. A. car, Internal carotid artery. Arach, Arachnoid zone. Cin, Neurone layer of medulla. 

 Cut, Cutis layer. Card', Card", Card'", Anterior cardinal vein. Card.L, Lateral branch of the cardinal vein. 

 Ec.gl, Ectoglia. Epen, Ependymal layer. G.tri, Trigeminal ganglion. N.-$, Oculo-motor nerve. N.4, 

 Trochlear nerve. N.$, Sensory root of trigeminus. N."j,8, Acustico-facial ganglion. Pia, Pia mater. 

 Raph, Raphe of the medulla oblongata. Ven.III, Third ventricle -of the brain. Ven.IV, Fourth ventricle 

 of the brain. X 50 diams. 



toward the median dorsal surface thereof, where it meets the correspondir - 

 of the opposite side, with \vhich it then unites to form a siagle me(' 

 This vessel ultimately acquires great siz "^^ is known as tht m-- x 



dinal sinus. T t is, V>\vn in figure 17?. 

 in the median 'ine, pc -ist to form 



of the vessels 

 of the ;' ' 



