SrNOIfYMS AND BEFBRENCES. 487 



have not accurately compared it with the correspouaing part in man. As indicated by 

 the synonym, the restiforme is sometimes regarded as identical with the postjiedunculns, 

 but even if they contain the same fibers, the latter should probably be defined as the con- 

 tinuation of the former to the cerebellum (Quain, A, II, 505). 



Between the restiforme and th^; Area ovalis is a smooth rounded elevation which we 

 have not been able to identify. Nearly opposite the cephalic end of the Area elliptica it 

 ceases, apparently covered in by the union of the parts at its sides. 



§ 1310. Rhinencephalon (az.), rhen.— Fig. 110-113, 116, 117; PI. I, Fig. 1, 3 • PI II 

 Fig. 3, 4 ; PI. IV, Pig. 15-19 ; § 1061. Quain, A, II, 755. 



This name seems to have been employed first by Owen (A, I, 383) as a convenient des- 

 ignation of the olfactory lobes and their crura. The observations of Milnes Marshall (.3), 

 as presented by Balfour (A, II, 383), require considerable modification of the views here 

 adopted respecting the constitution of the encephalic segments. The term rhinenoepTiola 

 is used by Balfour (A, II, 366) ; § 1150. 



§ 1311. Rhinocoelia, rJic..—Fig. 110-113; PI. IV, Fig. 16; § 1150. Gray, A, 115; 

 Meynert (Strieker, A, Fig. 261). 



Sj/n. — Ventriculus lobi olfactorii, ventricnlus rhineucephalicus, ventriculus olfactorius. 



The cavity of the Lobus olfactorius, communicating with the ventro-cephalic part of 

 the praecornu. Though slender in the cat, it is perfectly distinct, but is either obliterated 

 in the adult human subject or so smaU as to have escaped notice. The human olfactory 

 lobes are rarely obtained in a fit condition for accurate observation. 



§ 1313. Rima, r.— Fig. 118, 131 ; PI. Ill, Fig. 11 ; PI. IV, Fig. 14 ; §§ 1083, 1144, 1155. 

 Gray, A, 637 ; Quain, A, II, 544. 



Syn. — Rima transversa cerebri magna, fissura transversa magna, fissura Bichatii. 



The line of atrophy or abrogation of the proper nervous parietes of the procoelia from 

 the dorsal end of the porta to near the tip of the medicornu. Along this line there enters 

 either the margin of the velum, which is a fold of pia, or vessels therefrom, to constitute 

 the proplexun. Since, however, the endyma is continued from the margins of the rima 

 upon the intruded pia or vessels, these latter can be said to enter the proccelia only in the 

 sense in which an abdominal viscus enters the peritoneal cavity. 



Of the two margins of the rima, one is certainly formed by the fimbria, which is con- 

 tinuous, through the hypocampa, with the caudal and thus with the dorsal part of the 

 hemisphere. Concerning the other margin we are in doubt. In man it is probably the 

 Tcmia (semicircularis), but this part has not yet been identified in the cat, and we have 

 not personally examined, the Cauda striati. We content ourselves, therefore, with the 

 general statement that the fimbria lies in the Sulcus limitans and that the procoelian 

 endyma is reflected upon the proplfexus from' the fimbria and from the striatum or such 

 other parts as may form the cephalic slope of the Sulcus. At about 3 mm. from the tip 

 of the cornu the rima ceases, and the cornu is completely encompassed by nervous sub- 

 stance. 



The Name. — The terms above enumerated are not, strictly speaking, synonyms. They 

 were all applied under a misapprehension still commonly entertained that there is a lack 

 of (M the coelian parietes along a line extending between the tips of the medicornua, so 

 that the medicornua and diaccelia were in direct communicatioli both with each other and 

 with the ectal surface of the brain. With human brains in the condition in which they 

 frequently are obtained, removed without sufficient care and roughly handled.-such a solu- 

 tion of continuity may easily be demonstrated ; but it is certainly artificial, and the names 

 apnlied to it need not be retained in the same sense. To avoid, however, tha introduction 

 of a new term, the senior author proposed (J>, 136 ; 14, 541) the single short word rima 



