182 



STUDY OF PIG EMBRYOS. 



to the trigeminal ganglion, A^. 5. The vein is cut twice, Jug' and Jug" , for it 

 curves around the ganglion, passing on the inside of the ganglion between it and 



N^.ii. 



Veii.iv. 



Ven.iii. 



Fig. 115. — Pig, 12.0 mm. Transverse Series 5, Section ic 

 Ec, Ectoderm. F.b, Fore-brain. Inf, Infundibular gland. Jug* , Jug" , Jugular vein. N.^, Trigeminal gan- 

 glion. N.j,8, Acustico-facial ganglion, ^-g, Ganglion nodosum of the glossopharyngeal nerve. N.io. 

 jug. Jugular ganglion of the vagus nerve. N.ii, Root of the spinal accessory nerve. Md, Medulla oblon- 

 gata. Otf Otocyst. Str, Striae acusticae. Ven.iii, Third ventricle. Ven.iv, Fourth ventricle. X 22 diams. 



the wall of the brain. At this stage, however, it has begun to expand outward 

 behind, in front of, and below the ganglion. The expansion of the vein outward 



