AX IDEAL SIMPLE BRAIN. 



409 



1039. TABULAR ARRANGEMENT OF THE NAMES OF THE PRINCIPAL 

 PARTS OF THE AMPHIBIAN BRAIN. 



Segmenta. 



Rhinencephalon. 



n f Cephalic por- 

 tion, paired. 



9. -l 



Caudal por 

 tion, un- 

 paired. . . . 



Diencephalon. . . 



Mesencephalon. 



Epencephalon . . 

 Metencephalon.. 



Cavitates. 



Parietes. 



RhinoccElia. 

 i- ProccElia... 



) Proccelia.. 

 'y Porta. 

 ) Aula, az... 



Diaccelia, az 



i Mesocoelia, 

 } az 



Epiccelia, az. 



\ MetaccElia, 

 / az 



Lobus olfactorius 



Hemisphaera 



Hemisphaera 



Ji Aulatela (roof), az 



'( Terma (end and floor), az. 



r Thalamus (wall) 



I Diatela (roof), az 



Conarium (roof), az. 



Tuber cinereum (floor), az 

 ( Opticus (roof and wall). . . 

 ■ Valvula, in part (roof), f/z. 

 ( Crus (floor), 



Cerebellum (roof), az. 



Valvula, in part (roof), az. 



j Metatela (roof ^, az 



( Medulla (wall & floor), az. 



Commissurae et Plexus. 



Pseudo-commissura, az. 

 Proplexus. 



j Proplexus. 

 ( Portiplexus. 

 Auliplexus. 

 PrEecommissura, az. 

 Postcommissura (roof), az. 

 Diaplexus. 



Chiasma (floor), az. 



Metaplexus, az. 



§ 1070, An Ideal Simple Brain. — In accordance with the 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. 110-112. Schematic Diagrams of an Ideal Simple Brain. — Fig. 110 — Longi- 

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

 encephalic segments and tlie relations of the cceliae. 



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

 constitution of the ccslian floors and roofs. 



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



§ 1071. Comments upon 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 ])roperty of neurologists ; they are intended merely as visual aids to 

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

 the names thereidth. 



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

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

 Menobranchus, but differ from the former in the disjunction of the Ldbi olfactorii, from 



