AN IDEAL sniPLE BRAIN. 



409 



§ 1069. TABULAR ARRANGEMENT OP THE PRINCIPAL PARTS OF THE 



AMPHIBIAN BRAIN. 



Segments. 



Prosencephal . 



Diencephal . . . 



Mesencephal.. 

 Epencephal.. . 



Metencephal.. 



Cavities. 



fProsocoele, az., 

 including aula, 

 az., porta and 



[proccEle. 



Diaccele, az.. . . 



rMesocoele, az., 

 including iter, 

 az., pyla and 



toptoccEle 



Epicoele, az.. . . 



Metaccsle, az. . 



Parietee. 



(Hemicerebrum 

 Olfactory lobe 

 Terma, az., end and floor. 

 Aulatele, az.. roof. 



{Thalamus, side 

 Tuber cinereum, az., floor. . 

 Hypophysis, az 

 Diatele, ajz., roof 

 Conarium, az. 



(Optic lobe, roof and side. 

 Crus, floor. 



{Cerebellum, az., roof. 

 Valvule, az., roof. 

 Preoblongata, az., floor and 

 sides. 



( Postoblongata, az , floor and 



\ sides 



I^Metatele, az., roof. 



Commissures and Flexes. 



Precommissure, az 

 Prosoplex, az. 



Postcommissure, az. 

 Supracommissure, az. 

 Chiasm, az. 

 Diaplex. 



Metaplex, az. 



% 1070. An Ideal Simple Brain. — In accordance with tlie gen- 

 eral plan of this work and the propositions given above (§ 1051), 

 the examination of the actual brains of the frog and cat may be 

 advantageously prefaced by the careful study of the preceding dia- 

 grams (Fig. 110-112), which present to the eye certain essential and 

 fundamental facts. 



Fig. 110-113. Schematic Diagrams of an Ideal Simple Brain. — Fig. 110 — Longi- 

 tudinal dextro-sinistral section, showing the relations of the cavities, the sequence of the 

 encephalic segments and the relations of the ccelise. 



Fig. Ill — Mesal aspect of the right half after hemisection, showing the contour and 

 constitution of the ccelian floors and roofs. 



Fig. 112 — Transection of several segments, showing the coelian parietes. 



§ 1071. Comments vpon the Diagrams of the Brain. — Aside from the prominence given 

 to the aula, these diagrams, so far as they are correct, convey no information or ideas not 

 already the common property of neurologists ; they are intended merely as msual aids to 

 the student in the somewhat onerous task of learning the sequence of parts and associating 

 the names therewith. 



They do not accurately represent the actual condition of things in any known brain at 

 any stage of development. They correspond most closely with the brains of the frog and 

 "Menobranchus, but differ from the former in the disjunction of the Lobi olfactorii, from 



