ORIGIN OF THE CEREBRAL NERVES. 507 



arranged nerve corpuscles, which also appears to belong to the masses 

 of origin of this system, is found attached to the anterior border of the 

 root of the fifth. 



The masses of origin of the lateral root system are connected 

 with the crus cerebri (1) through the fibres rectce of the 

 raphe which penetrate into the fine fibrous masses of the 

 median nuclei and of the eminentiae teretes which bend to- 

 wards the emergence of the roots, and have been described by 

 Deiters as marginal fibres surrounding, but not belonging to, 

 the hypoglossal nuclei (figs. 257, 258, x 4 R, xi 3 R)-, (2) 

 through the fibres arcuatce immediately adjoining the grey 

 floor, which pass from the raphe' into the vago-accessory 

 nucleus (Stilling, Schroder, Clarke, Gerlach). Two other pro- 

 longations of the crus cerebri in the middle lateral system of 

 the medulla oblongata pass directly into its root fasciculi. 

 They form the first in the enumeration of the root fasciculi of 

 the lateral mixed system. 



1. The ascending root common to the glossopharyngeal 

 vagus and accessory nerves represents the " solitary fasciculus," 

 already known to Stilling and Lenhossek, that lies beneath the 

 grey floor at the inner border of the cerebellar peduncle, and is 

 applied lower down to the inner border of the posterior column 

 (fig. 257, without lettering; fig. 258, W). Its fasciculi proceed 

 from the raphe' within the planes of origin of the superior 

 accessory roots, just above the decussation of the pyramids. 

 They probably arise from the pyramids, or from the crusta of 

 the crus cerebri. They form, counting from behind, the second 

 series of the fibrse arcuatse, and become aggregated towards the 

 transverse sections of the above-mentioned ascending root, 

 which, as soon as it is within the planes of origin of the vagi 

 nerves, receives no further additions from the fibrse arcuatse. 

 This fasciculus contains, near the border, nerve corpuscles which 

 are for the most part of small size (21 30 fj, long, and 9 p thick)^ 

 and break it up into very fine sinuous bands that partly 

 gradually pass as rootlets into the accessory and vagal nerves^ 

 and partly curve round in considerable numbers above into the 

 glossopharyngeal nerve. This curve is occasioned by the pre- 

 sence of a cluster of the above-named small corpuscles that are 



