462 



THE RABBIT. PHYLUM CHORDATA 



each of which bears on its outer side a small lobe, known as the 

 flocculus. The lower side of the hind-brain is crossed m front by a 

 wide flat band of transverse fibres, the pons Varohi, which 

 connects the two halves of the cerebellum. Behind the cerebellum 

 the medulla oblongata, with a space, the fourth ventricle, m it, 



^. 





Fig. 363. The solar plexus and neighbouring structures in a rabbit, exposed by 



opening the abdomen and drawing the stomach to the right. 



a.m.a.. Anterior mesenteric artery ; coel.a., coeliac artery ; coel.g., one of the cceliac ganglia ; d.ao., dorsal 

 aorta ; i.v.c, inferior vena cava ; l.r.a., left renal artery (represented somewhat too large) ; l.r.v.. left 

 renal vein ; Ir., liver : as., oesophagus ; rm.. rectum spl.n., left splanchnic nerve ; sr.b., suprarenal 

 body ; St., stomach ; sy.c, sympathetic cord ; vag., left vagus. 



narrows backwards into the spinal cord. It is marked by a ventral 

 fissure bordered by two longitudinal bands or pyramids. 



There is no ventricle in the cerebellum, but small offsets of 

 the aquaeductus Sylvii, the cavity of the mid-brain, enter the 

 corpora quadrigemina. The third ventricle in the thalamen- 

 cephalon is deep, but very narrow, and is crossed by a large 

 middle commissure, which connects the thalami. The lateral 

 ventricles in the hemispheres are wide, shallow, and curved. 



