28o Anatomy of the Rabbit. 



(e) The posterior ftmiculus, in passing forward from the cord, 

 is divided into medial and lateral portions. The medial , 

 portion, the fasciculus gracilis, forms a narrow. band ter- 



t minating forwards in a club-shaped 'expansion, the clava. 



The lateral portion, the fasciculus cuneatus, passes into 

 the restiform body. 

 6; The brain may be divided by a median vertical section, and 



one-half examined from the medial surface (Fig. 87). In addition 



to many of the features already made out ■ on the surface the 



following, may be noted : 



hp- 



T T I T d... 



ell 



Fig. 87. The brain in median section: a., anterior commissure; a. c, cerebral 

 aqueduct; b.o., olfactory bulb; cb., cerebellum; c.cl., corpus callpsum; c.f., 

 body of the fornix; cl.i., inferior coUiculus; cl.s.', superior colliculus;" jc.m., mam- 

 illary body; c.o., optic chiasma; c.p., pineal body; fl.c, cervical .flexure; h., 

 habenular commissure; h.c, cerebral hemisphere; hp., hippocampui5;^inf., infundi- 

 bulum; l.t.,laminalterminalis; m.o., medulla oblongata; p.,posterior'commissure; 

 p.c, chorioid plexus of the third ventricle; pd.c, cerebral peduncle; pn.,'pons; 

 sp., splenium; s.pL, septum pellucidum; t.c, tuber cinereum; th,, thalamus, 

 massa intermedia; v.m.a., anterior medullary velum; v.m.p., posterior medullary 

 velum; v.q., fourth ventricle; v.t., third ventricle. I, olfactory nerve (origin); 

 II, optic nerve. 



(a) The deep but extremely narrow cavity formed by the third 

 ventricle is the first space appearing in the brain from the 

 anterior end, the first two (paired) ventricles lying laterally 

 in the hemispheres. They are connected with the third 

 ventricle by a narrow transverse canal, the interventricular 

 foramen (foramen interventriculare). 



(b) The anterior boundary of the third ventricle is formed ven- 

 trally by the narrow partition separating the two hemi- 

 spheres, in the dorsal portion of which is the small anterior 



