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corpus mamiillare, infundibulum, lobi inferiores, saccus 
vasculosus and pituitary body). 
D. Fore -Brain.—This may be considered as including 
the epistriatum, striatum proper and the membranous 
pallum, together with the bulbus olfactorius. 
The roots of the cranial nerves will be described in 
the section on the nerves. 
In a dorsal view of a well-preserved brain we note the 
following characters :—First the relatively small size of 
the brain. This is seen also in the Cod and in Teleosts 
generally. The small brain lies in the large cerebral 
cavity, surrounded by a packing of areolar connective 
tissue loaded with fat, and seems to be very dispropor- 
tionate to the size of the fish. Then the asymmetry of it 
is at once striking. The spinal cord, on entering the 
brain case, turns slightly to the left, but opposite the 
cerebellum it swerves markedly to the right, so that a 
median line would pass through the left striatum instead 
ot between the two striata. 
In the medulla the great reduction of the terminal 
bud system that has taken place involves the absence of 
the lobi vagi. Also the lateral line system is not suffi- 
ciently robust to have produced that exaggeration of the 
tuberculum acusticum known as the lobus linee lateralis. 
The medulla is therefore smooth, and presents no obvious 
traces of its ganglia. On removing the vascular covering 
of the fourth ventricle known as the choroid roof, the 
ventricle itself is seen to be apparently divided into two 
parts by the partial union over its roof of the medio-lateral 
portions of the tuberculum acusticum, forming an elliptic- 
shaped opening behind (calamus scriptorius) and a 
triangular one in front, with its apex directed backwards. 
The cerebellum, of which the body only is visible in the 
undissected brain, is small and globular. This is what 
