166 BULLETIN OF THE 



those described as lying between the two pairs of giant cells are my 

 fourth pair. His figures do not fully agree with this, however. His 

 Figure 2, Gz, shows the " anterior giant cells," which are clearly my 

 commissural cells; Figure 11, Gz, which he regards as one of the same 

 pair, has more of the appearance and position of a cell of the fifth pair. 

 The dorsal cells are described as salivary glands {Spdz, Figs. 1, 2, 11), 

 and it is curious that he has nowhere represented the prominent pro- 

 cesses (stalks) of these cells, unless, indeed, they are the structures 

 labelled Gz F (Y'lg. 12). Although the position is somewhat peculiar, 

 they certainly look more like the stalks of the dorsal cells than like 

 processes of the cells marked Gz in the same figure, which is his inter- 

 pretation, since the latter usually extend directly backward. 



Biirger expresses a doubt that the posterior giant cells (i. e. my fifth 

 pair) lie opposite each other. If not, it was because of some deformity 

 or twisting of the head, as they evidently are opposite each other in my 

 preparations (Figs. 63, 85), Instead of being nearer together than the 

 other cells, as he maintains (p. 640), they are certainly farther apart 

 than the components of any other pair (see my Figs. 63, 85). 



y. Fibrous Mass. — The central fibrous portion of the brain shows 

 few definite points of structure. The fibres run in every direction ; one 

 finds few commissural bands, and in general no fixed arrangement. At 

 two points, however, one notices (Fig. 99) vertical bands of fibres which 

 divide the brain into three parts, a central and two lateral portions, 

 which in position correspond to the three divisions of the ventral nerve 

 cord, which will be described later. The dorsal commissure (Plate VI. 

 Fig. 80, corns, os.) is very meagre, being cut in only two or three sections. 

 The number of fibres in it is consequently small, but there are at least 

 four large nerve processes ; two belong to the third or commissural pair 

 of cells, the other two perhaps to the second pair. A few finer fibrils 

 accompany these. 



In the female the brain measures only 0.08 mm. in length, and 

 0.1 mm. in width. In consequence of its more compressed form, the 

 cells stand closer together, and are more difficult to study. One finds 

 exactly the same number of large ganglion cells, and they occupy corre- 

 sponding locations. It may, then, be fairly assumed that the processes 

 are distributed in the same manner, although I was unable to follow 

 them as clearly as in the male. 



In total preparations (Fig. G3) one often sees groups of fibres passing 

 finteriad from the brain into the front wall of the anterior chamber. As 

 has been shown from sections, however, this is all solid tissue in front of 



