24 MAMMALIA. 



shallow grooves. In the small Monkeys with claws, as Midas, they 

 are nearly quite flat. In the Dog, the Otter, and the Seal, among 

 the Carnivora, the convolutions are far more numerous than in the 

 Feline tribes, as is the case also in the Horse and the Ruminant. 

 The Elephant is remarkable for a well-developed cerebrum, provid- 

 ed with numerous deep furrows. In the ordinary Apes the furrows 

 are fewer in number than in the last-named orders, and are defi- 

 cient in symmetry upon the two sides. The grooves are still more 

 numerous in the brain of the Dolphin, which is so remarkable for its 

 rounded form. The ventricles and choroid plexuses resemble those 

 of Man ; yet it is usually only the anterior and middle or descending 

 cornu of the lateral ventricle which is developed, the posterior oc- 

 curring in those orders only where the posterior cerebral lobes are 

 present. The lesser pes hippocampi is almost always wanting, 

 while the cornu Ammonis with the corpus fimbriatum is usually 

 found very large, c. g. in the Rodentia. In like manner the fornix 

 and septum lucidum are met with. The concretions of the pineal 

 body are wanting. The lateral ventricles communicate in those 

 orders which are furnished with conspicuous mammillary processes 

 or ganglia for the olfactory nerves, namely, in the Rodentia, Rumi- 

 nantia, Pachydermata, Edentata, Marsupiata, and Ferae. These 

 ganglia form triangular, obtuse projections beneath the anterior lobes 

 of the cerebrum. 



The brain of the highest Apes, as the Orang-utang and Chim- 

 panzee, approximates more to that of the human subject ; it differs 

 however in the very inferior proportional development of its hemis- 

 pheres (the convolutions of which are at the same time more numer- 

 ous and asymmetrical than in the rest of the Apes), as opposed to the 

 cerebellum, which is still however covered by the posterior lobes of 

 the cerebrum in old animals, as in Apes generally, e. g. Celeus capu- 

 cinus. The digital impressions upon the cornu Ammonis occur only 

 in the higher Apes. The brain of the Chimpanzee is more anthro- 

 poid than that of the Asiatic Orang-utang. 



The nerves arise and are distributed after the human type, from 

 which the olfactory pair exhibit the most departures. They are 

 probably entirely wanting in the Celacea, as the Dolphin, or are 

 present only as very fine thread-like rudiments. In other animals 

 they form, on the contrary, large hollow clavate organs, provided 

 with numerous ganglia, which proceed from the mammillary pro- 

 cesses. They are smaller and correspond with the human form in 

 the Apes. The animals which have very small rudimentary eyes, 



