272 TSE DESCENT OF MAN 



acteristics found only in the group of tlie Arctopithecine Pri- 

 mates. But it is equally true, as Grratiolet remarks, that, 

 m its widely open Sylvian fissure, it differs from the brain 

 of any actual marmoset. No doubt it would be much more 

 similar to the brain of an advanced foetus of a marmoset. 

 But we know nothing whatever of the development of the 

 brain in the marmosets. In the Platyrhini proper, the only 

 observation with which I am acquainted is due to Pansch, 

 who found in the brain of a foetal Gebus Apella, in addition 

 to the Sylvian fissure and the deep calcarine fissure, only a 

 very shallow antero-temporal fissure {scissure parallUe of 

 Gratiolet). 



ISTow this fact, taken together with the circumstance that 

 the antero-temporal sulcus is present in such Platyrhini as 

 the Saimiri, which present mere traces of sulci on the ante- 

 rior half of the exterior of the cerebral hemispheres, or none 

 at all, undoubtedly, so far as it goes, affords fair evidence 

 in favor of Gratiolet's hypothesis, that the posterior sulci 

 appear before the anterior, in the brains of tne Platyrhini. 

 But it by no means follows that the rule which may hold 

 good for the Platyrhini extends to the Gatarrhini. We 

 have no information whatever respecting the development 

 of the brain in the Cynomorpha ; and, as regards the An- 

 thropomorpha, nothing but the account of the brain of the 

 Gibbon, near birth, already referred to. At the present 

 moment there is not a shadow of evidence to show that 

 the sulci of a chimpanzee's, or orang's, brain do not appear 

 in the same order as a man's. 



Grratiolet opens his preface with the aphorism, "II est 

 dangereux dans les sciences de conelure trop vite. ' ' I fear 

 he must have forgotten this sound maxim by the time he 

 had reached the discussion of the differences between men 

 and apes, in the body of his work. No doubt, the excellent 

 author of one of the most remarkable contributions to the 



t'ust understanding of the mammalian brain which has ever 

 >een made, would have been the first to admit the insuffi- 

 ciency of his data had he lived to profit by the advance of 

 inquiry. The misfortune is- that his conclusions have been 

 employed by persons incompetent to appreciate their foun- 

 dation, as arguments in favor of obscurantism.'" 



But it is important to remark that, whether Gratiolet was 



^ For example, M. I'Abb^ Leoomte in his terrible pamphlet, "Le Darwinisme 

 etrorigjne de rHomme," 18'73. 



