1881.] 04:J [Wilder. 



the less extent of the pons, and the less degree of flexure of the whole 

 brain at the mesencephalic region. 



The greater width of the Tractus postrMnalis {Tr. prh.), which includes 

 the surface of the Lobulus hypocampoe {LI. limp.). In man, indeed, this 

 part is hardly visible on account of the prominence of the convolutions 

 latei'ad of the F. postrMnaUs. 



The apparent origin of the N. oculomotorius {N. ocm.) laterad of the 

 meson, and just caudad of the cimbia {cmb.). 



The appeai'ance of a division of the ectal layers of the pontile fibres into 

 three groups, cephalic, caudal and intermediate, the latter partly over- 

 lapped by the other tAvo. 



The appearance of a faint band crossing the trapezium a little obliquely 

 between the origins of the NR. abduceiis {N. ahd.) and facialis (]^. /.). 

 The distinctness of this band varies. 



The origin of the JV". hypoglossus {N. Jig.) laterad of the Area elUptica 

 (J.?-, el.), which might otherwise be taken as the surface of the oUva 

 or " olivary body " of man. The determination of this point involves 

 some comparisons and sections whicii I have not yet made, so I merely in- 

 dicate the part by a descriptive name and leave the question open. 



The close association of the roots of the NJSf. glossopharyngeus {N. gph.), 

 'oagus (i\r. «.), and accessoriiis {I^. ac). The long caudal nerve is of course 

 accessorial, and the cephalic funiculi are unquestionably glossopharyn- 

 geal ; but how the intermediate funiculi should be assigned, I am not yet 

 sure.* 



The marked prominence of the ventro-lateral region of the metence- 

 phalic continuation of the Columna lateralis myelonis {Clm. I.), forming an 

 elevation to which I have applied the provisional name Area ocalis 

 (At. ov.). 



The absence of any superficial decussation of the pyramids (py.). 

 Hence, the F. ventrimesalis {F. vms.) or "anterior fissure," is uninterrupted. 

 The F. ventrilateralis (F. vl.) is deflected at the caudal end of the Area 

 elUptica. 



Fig. 4. — The mesal surface of the right half of the brain (hemiencepha- 

 lon dextrum). Enlarged two diameters. 



The general features are from the same brain as fig. 3, but some features 

 are derived from prep's 290, 304 and 454. 



The surfaces shown in this figure are of four kinds, as follows : — 



1. The natural surfaces which are covered hj pia. These are the mesal 

 aspects of the hemisphere (Jiem.), and the Lohus olfactorius (Z. ol.). 



2. The natural mesal surface {Ar. spt.) of the right half of the septum 

 lucidum, which, in the cat, is in contact with its lateral homologue, or 

 separated therefrom only by a thin layer of connective. I have never 

 observed an interval corresponding to the pseudoccelia or "fifth ventricle " 

 of man. 



*In a paper on the N. vagus in the cat, presented at the same time with 

 this, Prof. T. B. Stowell has given a fuller account of the relations of these 

 nerves. 



