TRANSVERSE SECTIONS OE EMBRYO OF 12 MM. 



179 



trigeminal ganglion, the wall of the fore-brain, and the wall of the hind-brain will 

 be at once identified, so that the correspondence with the general figure is easily 

 followed. Between the trigeminal ganglion and the fore-brain are four veins, 



Ec.gl. N.J, 8. Cin. 



Epen . Raph . Ven. 1 V. 





A. has. 



Pia. 



'■.'■■■.'■'J :ii0Mi 

 ■'■'■• ^^^m 



7 ^§.?',:.^%vv- 



Veil. III. 



Arach 



Fig. 114. — Portion of Fig. 113 More Highly Magnified. 

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

 Cut, Cutis layer. Ec.gl, Ectoglia. Epen, Ependymal layer. G.tri, Trigeminal ganglion. J^g', J^'g" ■> 

 Jug'", Jugular vein. Jug.L, Lateral branch of the jugular. N.^, Oculomotor nerve. N.4, Trochlear 

 nerve. N.^, Sensory root of trigeminus. A^.y,8, Acustico-facial ganglion. Pia, Pia mater. Raph, 

 Raphe of the medulla oblongata. Ven. Ill, Third ventricle of the brain. Ven. IV, Fourth ventricle of the 

 brain. X 5° diams. '""*" 



two of which. Jug' and Jug'" , are larger and are parts of the main jugular stem 

 passing from the region of the hind-brain to that of the fore-brain, while the two 

 .smaller ones. Jug" , are merely branches of the jugular. Close to the section, 



