442 PROFESSOR G. ELLIOT SMITH. 



the brain. So that he thus spares himself the inconsistency of 

 some of his less cautious followers, who at one and the same 

 time adopt the views of His, Turner, and Broca, apparently 

 without appreciating the fundamental distinctions between the 

 three teachings. 



There are much wider grounds for objection to the subdivision 

 suggested by His than the comparatively minor reasons ' just 

 urged ; but as these major considerations apply equally to all 

 the current opinions, they will be best discussed after the views 

 of Turner and Broca have been considered. 



-■■'One of the two minor inconsistencies of His's subdivision, 

 which were indicated in the above remarks, calls for further 



-mention in order to clinch the matter. I refer to the separa- 

 tion of the so-called " stria olfactoria lateralis " (which is really 

 part of the anterior extension of the pyriform lobe) and the 

 "lobulus hippocampi" (which is merely the caudal extremity 

 of the same histological formation). 



This error is one which the human anatomist is very liable to 

 commit when his observations are not checked by comparative 

 studies, because the cephalic part of the pyriform lobe has 

 dwindled to such insignificant proportions that the name stria 

 oJfadoria, which is thus applied to it, is not altogether inap- 

 propriate. But in the early human foetus and in macrosmatic 

 mammals, in which the anterior part of the pyriform lol)e has 

 not undergone such an atrophic change (see fig. 1), it requires 

 no ai'gument to demonstrate that any definition which includes 

 the anterior part of the pyriform lobe in the rhinencephalon 

 must be not only arbitrary but also morphologically unnatural 

 if it excludes the rest of the pyriform lobe. Now, the natural 

 division between the pyriform lobe and the neopallium is the 

 rhinal fissure (fig. 1). And His, inconsistent though it may 

 seem with the above-quoted statements,^ freely admits that the 

 rhinal fissure is the line of demarcation between the "pallium" 

 and the " rhinencephalon." But he appears to entertain a mis- 

 conception as to the identity of the rhinal fissure. There can 



1 His tloes not deliberately excliiJe tlic pyiiform lobe from his rhiuenceplialon, 

 in fact, he seems to imaLriue tliat he has iiichuled it ; but in his list of parts of the 

 " olfactory lobe " he makes no mention of tlie tip of the nneiiiate convolution 

 (the i)ynfonn lobe). In other words, his " rhinencephalon '' is nothing else than 

 the " lobus olfactorius '' of the older German writers. 



