KNOX ON THE CETACEA. bU 



the cuttlefish, but no remains of anything in the intestines, and 

 no parasites. 



Heart and Vessels. — The heart weighed exactly one pound. The 

 Eustachian valve was small, that of Thebesius imperfect. The 

 aorta proceeded for about 3 inches of its course before giving 

 off any branches. At a point corresponding to the 15th or 16th 

 lumbar vertebra the vessel divided into the common iliacs. The 

 art. sacri media, its continuation, continued its course protected by 

 the Y-bones, and giving off branches corresponding to the inter- 

 vertebral spaces. 



Brain and Nervous System. — The erectile tissue surrounding 

 the spinal cord and origin of the spinal nerves in the Cetacea did 

 not extend into the interior of the cranium. The entire ence- 

 phalic mass weighed 2\ lbs. : cerebrum, 2 lbs. ; cerebellum, \ ; 

 pons and medulla, -j=2J. Compared with a drawing of Camper 

 of the Belphinus Fhoccena, the brain was found to differ remark- 

 ably, in being much broader in the line of the middle and poste- 

 rior lobes. In no animal did I ever find the fibrous structure of 

 the brain so well marked ; and this extended to the cerebellum *. 

 I give here some measurements of the brain, which may be of use 

 to future observers. The brain is short from before backwards, 

 but broad transversely : — 



Antero-posterior diameter 5f inches. 



Breadth 8 „ 



Greatest breadth of the cerebellum 4 „ 



Length of the cerebellar hemisphere . . . . 4f „ 



Depth of ditto 3f „ 



Weight of the encephalic mass 2^ lbs. 



Depth of the interhemispherical fissure . . If inches. 



Length of the corpus callosum 1^ „ 



Weight of cerebrum 2 "j 



„ cerebellum OJ \=^^ lbs. 



„ the pons and med. oblongata . . 0^ J 



Nerves. — The 7th pair was found to be unexpectedly large and 

 firm, including both portions. The anterior roots of the spinal 

 nerves were far more numerous than the posterior or dorsal. 



* " The substance of the brain is more visibly fibrous than I ever saw it in 

 any other animal, the fibres passing from the ventricles as from a centre to the 

 circumference, which fibrous texture is also continued through the cortical sub- 

 stance."— Huntee, " On Whales," ' Animal Economy,' Palmer's edit. p. 373. 



