86 



ANATOMY OF VERTEBRATES. 



sating fasciculus of the left prepyramid is shown at d! . The 

 fibres of the outer white neurine of the olives are longitudinal, 

 and are continued forward above the pons, as shown at /, fig. 66. 



The nucleus of grey matter sinks 

 deep into the macromyelon, as shown 

 in the sections, figs. 50, o and 57, g ; its 

 section in any direction presents the 

 undulated course of the white capsule 

 suggesting the anthropotomical term 

 6 corpus dentatum.' 



The lateral or restiform columns, 

 diverging, as in fig. 49, x, are mainly 

 continued into the cerebellum, of 

 which they form the hinder or 'in- 

 ferior peduncle,' fig. 66, r. Recruit- 

 ing grey neurine is developed in 

 their interior. The post-pyramidal 

 columns, contracting as they diverge 

 and ascend, are closely applied to the 

 restiform tracts, but are continued, as 

 the f fasciculi graciles,' into the crura 

 cerebri. 



Stilling l has enriched anatomy 

 with the following magnified view 

 of a transverse section of the macromyelon, one half of which 

 shows the structures as seen by transmitted light, fig. 57. The 

 anterior or ventral fissure, «, is here seen to be much deeper than 

 the opposite one, b, represented by the ' calamus scrip torius.' 

 The septum or raphe, c, of the lateral moieties is a compact white 

 neurine ; d, v, are the prepyramidal columns, of which r is the 

 large nucleus, s s the smaller nuclei; the roots of the hypo- 

 glossal nerve, /, run along the interspace between the pyramids 

 and olives. Of the latter the nucleus is shown at g, with its 

 plicated capsule of white neurine ; a small mass of grey substance 

 is situated near the olivary one at u ; x indicates grey matter and 

 i gelatinous matter, near the roots of the vagal nerves, k k. The 

 nucleus of the vagus is h, with the root of which nerve is also 

 connected the white longitudinal fibres, m. Whether g be ex- 

 clusively related to the hypoglossal, or is the place of origin (part 

 of the larger root) of the trigeminal, is undetermined ; n is the 

 ' soft column,' o the wedge-like column ; f is the nucleus of the 

 restiform body. The transverse or arciform fibres covering this 



Dissection of macromyelon, seen obliquely 

 from the right side. Man, xxxui". 



XVIII. 



