AN IDEAL SIMPLE BRAIN. 



409 



§ 1069. TABULAR ARRANGEMENT OF THE NAMES OF THE PRINCIPAL 

 PARTS OF THE AMPHIBIAN BRAIN. 



Segmenta. 



Rhinencephalon. 

 Cephalic por- 

 tion, paired. 



e 

 o 



"a 



0. 



Caudal por- 

 tion , un- 

 paired 



DIencephalon. . . 



Mesencephalon . 



Epencephalon . . 

 Metencephalon., 



Cavitates. 



Rhinocoelia.. 

 Proccfilia.. . 



Procoelia. . . 

 Porta. 

 Aula, az 



Diaccelia, az 



( Mesocoelia, 

 ( 02 



Epiccelia, as 



3 Metacoelia, 

 ( az. . . . 



Parietes. 



Lobus olfactorius 



Hemisphaera 



Hemisphaera 



( Aulatela (roof), az 



( Terma (end and floor), az. 



1 Thalamus (wall).. . , 

 Diatela (roof), az 

 Conarium (roof), az. 

 Tuber cinereum (floor), az. 

 i Opticus (roof and wall). . . 

 \ Valvula, in part (roof), az. 

 ( Crus (floor), 

 ( Cerebellum (roof), az. 

 \ Valvula, in part (roof), az. 



( Metatela (roof), az 



j Medulla (wall & floor), az. 



Commissuree et Plexus. 



Pseudo-commissura, az. 

 Proplexus. 



( Proplexus. 

 1 Portiplexus. 

 Auliplexus. 

 Praecommissura, 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 alaove (§ 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. 



Pig. 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 coeliffi. 



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

 constitution of the coelian floors and roofs. 



Pig. 113— Transection of several segments, showing the coelian parietes. 



8 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 tbe 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. , i, • * 



They do not accurately represent the actual condition of thmgs m any known bram at 



anv 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 LoM olfactom. from 



