ANATOMY OF THE NERVE CENTRES. 459 



The Brachia enter the sides of the capsule of the corpus 

 centrale. The fibres of which they are composed form the 

 greater part of the substance of the capsule, decussate in the 

 median line, and enter the opposite brachium. Some of these 

 fibres also probably descend to the crus through the peduncle. 



Cuccati [186] terms the corpus centrale the fan-shaped body, 

 and gives the following description of it in the Blow-fly : ' It 

 occupies the centre of the brain, its principal axis is directed 

 from above and in front, downwards and backwards ; it is dis- 

 tinctly divided into two parts, one of which is behind, and the 

 other in front. The posterior part appears like an open fan, 

 in sections perpendicular to its principal axis ; the anterior 

 part I term the body of elliptical section, owing to its form ; 

 it hangs by a fine net-like substance below the superior part.' 

 It is evident that Cuccati has described a section through the 

 posterior part of the capsule and the middle of the ellipsoid 

 body, and his fine net-like substance consists of the fibres of 

 the fillet, which spread out between the capsule and the 

 ellipsoid body. The above is all i\\zi has been hitherto pub- 

 lished, so far as I know, on the corpus centrale of the 

 Blow-fly. 



Viallanes has described the corpus centrale of the Cricket 

 [185, Mem. 5] as consisting of 'two zones or capsules, separated 

 by a curved plane parallel with its upper and lower surfaces.' 

 He adds : ' The superior is much thicker than the inferior 

 capsule, and its lateral edges overhang the edges of the inferior 

 capsule. The whole organ is somewhat compressed from before 

 backwards, and suspended in a loose fibrous reticulum (atmo- 

 sphere fibreuse). It divides below into two crura, which curve 

 from before backwards and are lost.' 



In the Wasp Viallanes [184, Mem. 4] says : ' The corpus 

 centrale may be compared to a hemisphere strongly com- 

 pressed from before backwards with a slightly concave base. 

 It receives fibres from all the important parts constituting the 

 protocerebron ; and these, before they are lost in the sub- 

 stance of the corpus centrale, form a fibrous atmosphere 

 around it.' 



