ANATOMY OF THE NERVE CENTRES. 457 



Dietl, although he does not mention the procerebral lobes, 

 has figured them in the Bee (Apis mellifica) [175, PL XXXVI., 

 Fig. i], in which they are apparently far larger than in the 

 Fly. The nodulus is also larger, and is shown in Dietl's 

 figure to be connected with the radiating fibres of the corpus 

 centrale. 



There is also a distinct indication of the procerebron in one 

 of Cuccati's figures [186, PL XX., Fig. 6] . It is to be regretted 

 that all Cuccati's figures are too small, and are insufficiently 

 described in the text. 



In 1870 I first discovered the procerebron in the Blow-fly 

 by removing the surrounding parts. I gave a figure of the 

 appearance they presented in a preparation made by dis- 

 section, displayed by the pressure of the cover-glass [62, 

 PL VII., Fig. 4], and I was able to state, as the result of the 

 rude methods employed in those days, that they are peduncu- 

 lated lobulated organs united by a well-marked median com- 

 missure. At the same time I suggested that they are possibly 

 analogous to the cerebral lobes of vertebrates, an opinion 

 which has been rendered more probable by my more recent 

 researches. 



I suspect that the parts described by Viallanes in the Cricket 

 as the lateral lobes of the median protocerebron consist in part 

 of the representatives of my procerebron, and in part of my 

 thalamic lobes. 



The Corpus Centrale (Fig. 59) is a complex commissure, 

 situated in the cavity of the cerebron, behind the nodulus, and 

 in front of the pyramidal ganglion. It is largely developed in 

 all the Insecta, but is apparently entirely wanting in the 

 Crustacea. Perhaps this remarkable body may be best de- 

 scribed by comparing it to a broad band folded S-wise. The 

 upper limb of the S forms the capsule (Fig. 59, c) ; it over- 

 laps the rest laterally, in front, and behind. The remainder 

 of the S forms what has been termed the ellipsoid body (c). 

 Between the capsule and the ellipsoid body is the hilus, into 

 which fibres from the nodulus pass ; these form the fillet of 

 the nodulus. 



