THE CEREBELLUM. 251 



Thus coordinated movements in response to sensory impulses are 

 directed by the mesencephalic and cerebral apparatus to be 

 described in future chapters, while the side circuit through the 

 cerebellum furnishes the means of maintaining the requisite tone. 

 It is evident that the cerebellum has changed its functions in 

 the course of vertebrate history but the indications are that the 

 broad functional relationships of its main parts have been retained. 

 The somatic sensory part has come in mammals to play a special 

 role in the senso-motor functions. It is still concerned chiefly 

 with the reactions of the organism toward the external world 

 by means of its somatic muscles. It is to be hoped that future 

 experimental studies will be directed toward discovering the 

 structural and functional relationships of the deep nuclei of the 

 anterior lobe. The suggestion that some of these are homologous 

 with the gustatory nucleus of fishes will be justified if it stimulate 

 investigation in this direction. 



DEMONSTRATION OR LABORATORY WORK. 



1. Review the laboratory work on the somatic sensory relations and 

 the structure of the cerebellum in fishes given in Chapters VI and VII. 



2. Study the structure of the cerebellar cortex in a mammal in 

 Golgi sections. 



3. Examine by dissections and by sections in various planes the 

 relations of the several parts of the cerebellum in fishes and mammals. 

 Verify the comparisons made above, especially the constancy of the 

 hemispheres in the vertebrate series, 



4. Examine in the same way the relations of the cerebellar peduncles 

 and of the secondary gustatory nuclei and the velum. 



LITERATURE. 



Bianchi, Arturo: Sulle vie di connessione del cervelletto. Archivio di 

 Anat. e di EmbrioL, Vol. 2. 1903. 



Barker, L. F.: The Nervous System. 



Bethe, A.: Die Locomotion des Haifisches u.s.w. Arch. f. d. ges. Physiol., 

 Bd. 76. 1899. 



Cajal, S. R.: Textura del sistema nervioso del Hombre, etc. Madrid. 1904. 



Catois, E. H.: Recherches sur Phistologie et Panatomie microscopique 

 de 1'encephale chez les poissons. Bull. Sci. de la France. Tome 36. 1901. 



Edinger u. Wallenberg: Untersuchungen iiber den Gehirn der Tauben. 

 Anat. Anz., Bd. 15. 1899. 



Van Gehuchten, A. : Le corps restiforme et les connexions bulbo-cerebel- 

 euses. Le Nevraxe, Tome 6. 1904. 



