ON THE RELATIONS OF MAN WITH THE LOWER ANIMALS 477 
mists divide the cerebral hemispheres of man into only two lobes, the 
anterior and the posterior, separated from one another by the fissure of 
Sylvius ; but it is more usual to speak of three lobes,! an anterior, a 
middle, and a posterior, the latter, or ‘third lobe, being the posterior, 
inasmuch as it consists of the hinder part of that, which those who 
divide the cerebral hemispheres into two lobes, call ‘posterior.’ It 
is in this sense that Cuvier, Meckel, and Tiedemann use the 
term, third or posterior lobe. It is generally admitted that no 
very strict line of demarcation is traceable between the middle and 
posterior lobes; anatomists being content to accept Cuvier’s curt 
definition :— 
“La partie du cerveau située au-dessus du cervelet est ce qu’on 
nomme le lobe posterieur du cerveau.” 2 
So far as I am aware, the terms “third” or “ posterior lobe,” have 
never been applied in any other senses than those which I have indi- 
cated. Under these circumstances, it is utterly incomprehensible to 
me how any one competently informed, either with respect to the 
literature or to the facts of the case, can assert that the hind lobe “ is 
peculiar to the genus Hfomo ;” for not only will the inspection of any 
ape’s brain convince one of the contrary, but the facts were originally 
ascertained and published by a most competent authority, and have 
never been doubted for nearly forty years. 
Tiedemann’s “ Icones Cerebrorum Simiarum,” published in 1821, 
in fact, ought to be familiar to every student of mammalian anatomy. 
On turning to his first Plate, one finds the first figure to be a repre- 
sentation of the brain of “Sziza nemestrina.” The explanation of the 
figures says: “a, lobus anterior paullulum acuminatus; 0, lobus 
1 Tt is not a very easy matter to determine with whom these divisions originated. Vesalius 
(Humani Corporis Fabrica, libri septém, 1DCXLII.) speaks neither of lobes nor of special 
‘prominentiz’ in the cerebral hemispheres, though he describes them very accurately, 
explaining particularly that the under surface of these hemispheres is adapted to the ‘ tubera,’ 
of the cranial bones. 
Varolius (Anatomiz sive de Resolutione Corporis Humani, libri iii., MDNCI. p. 131) 
says, in his letter to Hieronymus Mercurialis: ‘De nervis opticis multisque aliis preeter 
communem opinionem in humano capito observatis ;’ 
“Sunt autem tres cerebri prominentiz : anterior, media, et posterior . . . . postrema 
cerebri prominentia replet cavitatem productam 4 superiori parte occipitii 4 posteriori ossis 
sincipitis et ossis petrosi.”” 
This looks like the origin of the division into three lobes, while Willis seems to have 
originated the division into two. 
“Porro in homine cui cerebrum pre ceteris animalibus capax et amplum est, utrumque 
hemispherium rursus in duos lobos nempe anteriorem et posteriorem subdividitur : inter 
quos arterize carotidis ramus, utrinque instar rivi limitanei productus eos velutiin binas 
provincias distinguit.”—Willis, Cerebri Anatome, 1664. 
 Lecons d’Anatomie Comparée, 2de ed., tome iii., p. 44. 
