1881.] ^^'^ [Wilder. 



Pig. 2. — The sinistral aspect of the brain. From prep. 28S. Enhxrged 

 two diameters. 



Tiie Lobm olfactorias (L. ol.) is made somewhat too prominent. The 

 cur^red line upon its lateral surface indicates, approximately, tlie boundary 

 of the more cephalic portion of the pero or ectal layer, w.hence arise the 

 Neroi olfactorii. These nerves are not shown. 



The features of the Grus olfactorium indicated by Im. cin. and Im. alb. 

 are more fully shown upon fig. 3. 



The Nervus optkus {N. op.) j^rojects from the ventral margin of the fig- 

 ure, and the Fissura Sylmana {F.s.) is seen dorso-caudad of it. 



The ventral end of this fissure, as is always the case in the cat, joins the 

 fissure which forms the dorsilateral boundary of the Tractus olfactorius 

 {Tr. ol.), and the cephalic and caudal divisions of that fissure are called re- 

 spectively r7w«-afe's and postrMnalis {FF. rJi. and prh.). So much of the 

 hemisphere as lies caudad of the F. Sylmana forms the Lobus temporalis 

 (X. tmp.), the ventral extremity of which is the Lobulus JiypocampcB {LI. 

 7imp.). 



The cerebellum (c5f.) presents the narrow median lobe or vermis {mi.), 

 and the Lobus lateralis (L. I.). Near the ventricephalic angle of the lat- 

 ter, two or three of the laminae of the second tier project as the Lobulus 

 appendicular is {LI. ap.), which is seen better in fig. 3. 



The metapUxus shown in fig. 3 (mtpx. ), has been removed, so as to ex- 

 pose the prominent Eminentia, auditor ia {Em. aw.), whence springs the 

 N. auditorius {N. au.). 



Just ventrad of the eminence is the trapezium {tz.), and cephalad of this 

 is the pons (jjn). 



Between the pons and the hemisphere appears a part of the Orus cerebri 

 {Or. cb.), and cephalad of this is the slender If. trochlearis (K tr.), which, 

 by inadvertence, seems to emerge from the F. postrMnalis instead of from 

 between the cerebellum and the hemisphere. 



The N. trigeminus {JS'. trg.) has been cut short, in order the more clearly 

 to show that it emerges just caudad of the pons, and not through it 

 as in man. 



The remaining nerve origins are indicated only bj^ dots. Those of the 

 NI^. glossophary ngeus, vagus and accessorius (N2f. gph., v. and ac.) form a 

 series. At the side of the myelou, near the dorsal and ventral borders, are 

 seen the origins of the first cervical nerve (N. cv. 1.). 



In this figure the fissures are accurately represented as they are in the 

 preparation, excepting that the small F. lunata {F. In.), has been added 

 from prep's 519 and 530. The small F. intermedia might well have been 

 inserted between the dorsal ends of the FF. anterior and postica {FF. a 

 and^). 



Plate ii. 



Fig. 3. — The basis encephali, or ventral aspect of the brain. Enlarged 

 two diameters. 



The proportions and general features are from the brain of an adult 9 , 



PROC. AMEE. PHILOS. SOC. XIX. 109. 3q. PRINTED DECEMBER 28, 1881. 



