1 82 Journal of Comparative Neurology. 



ceeding with their description it should be noted that the inner 

 optic mass is so turned as to bring its posterior edge much closer 

 to the central brain mass than its anterior margin. It is at this 

 posterior margin that the entrance to the space between its two 

 lenticular portions is situated. 



From this opening emerge a large number of fibers gath- 

 ered into several bundles, the most of which terminate in the 

 adjacent posterior lower portion of the central proto-cerebron. 



Of these bundles Viallanes (87 ) distinguished four, and 

 Cuccati (88 ) seems to have found some of them in Soviouiya. 

 The inner optic region of this genus, as shown by the latter 

 author, differs so much from what I find in the bee or have seen 

 figured or described elsewhere that comparisons are very uncer- 

 tain. What he calls the ovoid body (eiformige Korper) doubt- 

 less corresponds to the inner optic mass as generally met with, 

 but what may be the homologue of his S-form body I am at a 

 loss to know unless it may possibly be the outer lenticular por- 

 tion considerably separated from the inner one. But in case 

 that were true, there would be an anomalous condition of fibers 

 from the concave face of the outer optic mass passing through 

 the space, a condition of affairs that is not true in the case of 

 the bee nor probably in any other hexapod. He also figures 

 and describes several tracts of fibers that apparently correspond 

 to some of those to be described here a few lines ahead, but as 

 originating from the outer surface of the S-form or of the ovoid 

 body, which, I take it, is equivalent to describing them in the 

 bee as arising from the outer surface of the inner optic mass, 

 and this is not true. 



But to proceed with the optic tracts, there may first be 

 described one, noted by both Viallanes (87) and Cuccati (88 )» 

 leaving the inner margin of the inner lenticular body and pass- 

 ing into the central proto-cerebral mass a little above the point 

 of entrance of the antero-posterior tract and continuing thence 

 as a loose band of fibers across the posterior region of the 

 brain and below the fibrillar arch to the inner optic mass of the 

 opposite • side, thus forming what may be termed the upper 

 optic commissure. It does not pass directly across but is 



