PHYSIOLOGY: PRACTICUM VIII: PLATE XXII. 



DORSUM OF SHEEP'S BRAIN AFTER THE REMOVAL OF PARTS OF THE 

 CEREBRUM AND CEREBELLUM. 



precormi 



4 

 intercerebral fissure 



sylvian f. 



olfactory bulb 



olfactory cms 



insula 



for nix 



3 



cauda of caudatum J 



habena 



medicommissure 



thalatnus 



pregeniculum 



postgeniculum 



conarium 



RHINENCEPHAI, 



PROSENCE- 

 PHAL 



DIENCEPHAL 



trochlearis nerve 



- - pregeminum 

 postgeminum ) 



pons 



flocculus 



cerebellum 



MESENCEPHAL 



EPENCEPHAL 



metatela 



- postoblougata ! MKTENCEPHAI, 



Compare with PI. XVIII. From the cerebellum have been cut the dorsal part 

 and also the caudal. On the cut dorsal surface are seen the central alba and the periph- 

 eral cinerea, but the outline of the latter is diagrammatic only. At the sides are the tiers 

 of foliums constituting the flocculus. 



From the cephalic end of the cerebrum have been cut the parts projecting over the 

 olfactory crura, but part of the cephalic slope marked b in PI. XVIII is here marked 1. 

 With the dorsal portion were removed the entire callosum and the fornix excepting the 

 cephalic vertical part. This and the mesal walls of the paracrele are really cut at a lower 

 level than the larger cut surface on the left. On the right the insula has been exposed by 

 pushing up and breaking off the overhanging parts. The ectal surfaces, covered by pia, 

 are indicated by irregular lines representing the blood-vessels. 



The ental surfaces, covered by endyma, are those of the caudatums in the paracreles, 

 the habenas, medicommissure and conarial pouch ; and the floor of the aula and p .rtas. 



The irregular line laterad of the habena and extending around the endymal area on 

 the conarium represents a ripa (shore-line). It consists ot the cut or torn edges of the pia 

 from the dorsum of the thalamus and of the endyma from the habena which united to form 

 a membranous roof of the diacoele, the DIATELA, which has been removed. 



Similarly the pial, dorsal surface of the thalamus is demarcated from the endymal sur- 

 face of the caudatum by a ripa which meets the other at the porta. 



The CONARIUM, although a constituent of the DIENCKPHAL, is tilted caudad so as 

 to rest upon the PREGEMINUM, and the mesal part of its exposed surface is likewise 

 covered by endyma. 



i, cephalic slope. 2, mesal wall of PARACCELE ; at a higher level this would be one 

 of the HEMISEPTUMS. 3. horizontal cut surface of cerebrum. 4, the mesal, vertical 

 portion of the paraccele. 5, indicates the location of the ripa between the thalamus and 

 caudatum, but it is overhung by the latter so as not to appear in this view. 6, extension 

 of the diacrele upon the conarium. 7, mesal furrow of the pregeminum. 



