HUMAN AND MAMMALIAN. 



In the cat the form of the different parts is very nearly intermediate between 

 the human medulla and that of the sheep. It is especially distinguished in this 

 region by the very remarkable size of the post-pyramidal and restiform nuclei, 

 which are developed to an enormous extent, filling the respective columns (Fig. 1). 



Fig. 1.. 



Posterior comu from the medulla of the cat, just above the decussation of the pyramids. — a, post-pyramidal 

 nuclei ; 6, restiform nucleus ; c, central canal ; d, tractus intermedio-lateralis ; e, caput coruu ; /, nucleus of 

 spinal accessory. 



(3.) In the next, section, Plates V, and XIV, Figs. 18, 18% the anterior cornua 

 have almost entirely disajjpeared, and the group of cells constituting the nucleus 

 of the hypoglossal {H) has become quite distinct. The nucleus of the spinal 

 accessory {S) is plainly seen, as a long tract of cells reaching from the tractus inter- 

 medio-lateralis to a point just behind the central canal. The lateral cornu through 

 which the roots of the spinal . accessory run, is here quite prominent, and just 

 beyond a line of cells can be traced connecting it with the antero-lateral nucleus. 

 Reichert seems to consider the antero-lateral nucleus as simply a pushing outwards 

 of the lateral cornu,'^ but I think this is not the case ; it seems to be more probably 

 a distinct group of cells, intimately connected with the development of the internal 

 arciform fibres and appearing at the same time with these. 



The commencement of the olivary bodies (0) is now seen as a somewhat elon- 

 gated tract of cells along the margin of the pyramids, closely connected with the 

 arciform fibres and with the antero-lateral nucleus. In the substance of the anterior 

 pyramids, which are here very large, and from which the raphe is already partially 

 formed, may be seen here and there little nuclei, connected with fibres both trans- 

 verse and longitudinal (Kleine Pyramiden-Kerne of Stilling). (Fig. 18", i.) 



The posterior portion of the medulla has undergone very considerable develop- 

 ment ; the caput (b) is filled with numerous scattered cells, and is connected with 

 the external arciform fibres by little groups of cells, which its numerous radiating 



* In his description of Fig. 7, op. cit., lie makes the following statement : Die seitlichen Homer 

 haben ihre Verbindung untereinander und zum Theil auch mit der Centralpartie der grauen Kernsub- 

 stanz aufgegeben, sie erscheinen als einzelne unbestimmt begrenzte, in die Seitenstrange des Mantels 

 eingelagerte Flecke die demnach als Durchschnitte von isolirt verlaufenden Strangen anzusehen sind. 

 p. 100. 



