202 The Descent of Man. Paut L 



"(liff.'is less fiom the cliinpanzee nr the oranR, tlian tliese do even 

 "from ihe monkeys, and that tlie difference hetween the brain of the 

 "chimpanzee and cf m>in is ahnost insigniticant, whfH conipaitd with 

 "that between the chimp;inzee brain and ihit of a Lemur." 



Ill the paper t'l whi. h I liave refi-rred, Pn.fessor Bi^ohoff does not 

 deny tlie second piirt of this st.tement, but he first makes tlie irrelevant 

 remark that it is not wonderful if the brains of an orang and a Lemur 

 are very different ; and secondly, goes on to assert thai, •' If we succes- 

 " sively comiisue the brain of aman with that of an orantr; the brain of 

 " tills wilh that of a chimpanzee ; of ihis with tha' of a i;orilla, and so 

 "on of a Nylobates, SemnopitliecHS, CynocepJialus, Cercnpitheous, Macaeun. 

 " debus, Callithrix, Lemur, btennps, Ilapale, we shad not meet with a 

 "greatrr, or even a& great a, hreak in the degree of ilevelopmeiit of fhe 

 "convolutions, as we find between toe br.iin of a man and that of an 

 " orang or chimpanzLe." 



To wiii'^h X reply, firstly, that whetlier this assertion be true 

 or false, it l^as nothing whatever to do with the proposition enunciated 

 in 'Man's Place in Natuie,' whi, h refers not to the development of the 

 convoluii ms alone, but to thestructuieof the whole brain. It Professor 

 Bischoff had takeu the trouble to refer to p. 96 of fhe work he criticises, 

 in fact, he would have found the following passage: "And it is a 

 "remarkable ciicuinstance that tliough, so far as our present know- 

 " ledge extends, there is one true structural break in tlie series of forma 

 " of Simian br.diis, this hiatus dc;es not lie between man and the 

 "manlike apes, but between the lower and the lowest Simians, or in 

 "other words, between the Old and New World apes and monkeys and 

 "the Lemurs. Every Lemur which has yet been examined, in fact, 

 " has its cerebellum jMi-tially visible from alDOve ; and its posterior lobe, 

 " with the contained posterior conm and hippocampus minor, moie or 

 "less rudimentary. Every marmoset, American monkey, Old World 

 " monkey, baboon, or manlike ape, on the conliai-y, has its cerebellum 

 " entirely hid.leii, posteriorly, by the cerebral lobes, and possesses a 

 " large posterior cornu with a well-developeil hippocanipus minor." 



This statement was a strictly accurate account of what was knowu 

 when it was made; and it does not appear to me to he more than 

 apparently weakened by the subsequent discovery of the relatively 

 small development of the posterior lobes in the Siamang and in the 

 Howling monkuv. Notwithstanding the exceptional brevity of tlic 

 posterior lobes in these two species, no one will pretend that their 

 Drains, in the slightest degree, approach those of the Lemurs. And 

 if, instead of putting Mapale out of its natural place, as Professor 

 Bischoff mobt unaccountably does, we write the series of animals 

 he has chosen to mention as follows : Homo, Pithecus, Tnyluihjtcs, 

 Hylubates, Semnopithecus, Cynocepludus, Cercopithecus, Macanus, Cebas, 

 Callithrix, Ha^jale, Lemur, iSteitaps, I venture to realtirm that Ihe 

 great break in this series lies fetween Hapale and Lemur, and that 

 tills break is consideiably greater than that between any other two 

 terms of that series. Professor Bischoff ignores the fact that long 

 before he wrote, Gratiolet had suggested the separation of the lemurs 

 from the other Primates on the very ground of the difference in their 

 cerebral characters ; and that Professor Flower had made the following 

 i/Dservations In the course of his description of the brain of the Js.vsiB 

 Loris.'* 



* TransactioaB of the Zoological Society,' vol. * mb2. 



