24 Journal of Comparative Neurology. 



of the nucleus funiculi, which no longer send dendrites into this 

 median dorsal region. The great majority of these cells, which 

 constitute the vagus lobe, are situated close to the central cav- 

 ity. Some of them are compact but with very rough or irreg- 

 ular bodies, while others are greatly elongated (c. g. 8 X 8o/i). 

 Behind the commissura infima Halleri some cells lie in or near 

 the middle line and send their dendrites to both sides. These 

 are to be regarded as belonging to the median nucleus of Cajal. 

 The dendrites are relatively short, thick, very profusely 

 branched, and the final branches are very slender sinuous twigs. 

 The great difference of form between the cells of the lobus vagi 

 and those of the nucleus funiculi is shown in Fig. 2i. The 

 neurites are traced laterally and ventrally into the lateral tracts. 

 The fibers are fine and in most parts of the lobe are not sufifi- 

 ciently numerous to form a bundle, so that it has been impos- 

 sible to trace them to their destination. They do not bend in 

 the direction of the arcuate fibers. 



The sensory fibers of X are mingled with the motor fibers 

 at their external origin, and after entering the medulla the sen- 

 sory fibers can not be traced in haematoxylin sections. In 

 GoLGi sections they are seen to run up from their point of en- 

 trance on the lateral surface of the medulla through the outer 

 part of the nucleus funiculi to enter and end in the lobus vagi. 

 The sensory IX runs deeper in the nucleus funiculi and 

 acusticum. 



The communis VII (Figs, i, ii, 1 1 a, 29, 30) is extremely 

 dif^cult to study owing to the fineness of its fibers, the com- 

 pactness and complexity of the root and ganglionic complex, 

 and the fact that the VII fibers are scattered in very small bun- 

 dles which must pass through the spinal V tract and the acusti- 

 cum to reach the front end of the vagus lobe. There is to be 

 noted first what appears in a single haematoxylin series to be a 

 strong general cutaneous component entering the spinal V with 

 VII. The fibers are fine and I am in doubt whether they are 

 general cutaneous and not rather communis fibers which pass 

 through the spinal V in a very much dispersed condition. Some 

 of the communis fibers of VII do thus pierce the dorsal part of 



