424 Mr, Hunter’s Obfcrvailom on the 
Tnefe fubftances arc nearly in the fame proportion as in the 
human brain. The two lateral ventricles are large, and in 
thofe that have olfactory nerves are not continued into them 
as in many quadrupeds ; nor do they wind io much outwards 
as in the human fubjefl, but pais dole round the pofterior 
ends of the thalami nervorum opticorum. The thalami them- 
ielves are large; the corpora ftriata imall; the crura of the 
fornix are continued along the windings of the ventricles, much 
as in the human fubjeft. The plexus choroides is attached to 
a ft roil g membrane, which covers the thalami nervorum opti- 
corum, and paftes through the whole courfe of the ventricle, 
much as in the human fubjeff. 
The fubftance of the brain is more vifibly fibrous than I 
ever faw it in any other animal, the fibres palling from the ven- 
tricles as from a center to the circumference, which fibrous 
texture is alfo continued through the cortical fubftance. The 
whole brain in the Piked Whale weighed four pounds ten 
ounces. 
The nerves going out from the brain, I believe, are fimilar 
to thofe of the quadruped, except in the want of the olfaflory 
nerves in the genus of the Porpoife. 
The medulla fpinalis is much fmaller in proportion to the 
fize of the body than in the human fpecies, but ftill bears fome 
proportion to the quantity of brain ; for in the Porpoife, where 
the brain is large!!, the medulla fpinalis is large!! ; yet this did 
not hold good in the Spermaceti Whale, the fize of the me- 
dulla fpinalis appearing to be proportionally larger than the 
brain, which was fmall when compared to the fize of thei 
animal. It has a cortical part in the center, and terminates 
about the twenty-fifth vertebra, beyond which is the cauda 
equina, the dura mater going no lower* The nerves which go 
2 off 
