Ken YON, The Brain of the Bee. 197 



cerebron to the antennal lobe within the region of the inner ter- 

 minations of the motor-fibers to the oral and ventral nerves. 

 In such preparations fibers leaving the tract may be readily seen 

 and it is not a connection between the antenno-motor nerves 

 and the ventral cord such as Cuccati (88) seems to imply in his 

 description of the same tract in Soinomya. Connecting the 

 pair of tracts in the ventro-cerebral region are four transverse 

 bands of fibers. These have been noted several times in bi- 

 chromate of silver preparations, but the longitudinal tracts to 

 the antennal lobe were found impregnated but once. 



The transverse oesophageal commissure seems to have be- 

 come completely fused with the ventro-cerebron in the bee, and 

 is apparently represented by a few transverse fibers found in the 

 lower floor of the oesophageal foramen. 



The Cell Groups. 



Having finished the description, incomplete though it be, 

 of the central fibrillar substance of the bee brain, there still re- 

 main the groups of cells clothing the mass to be discussed. 

 The location of these, after recognizing the general form of a 

 hexapod nerve cell, is of little physiological importance com- 

 pared with the extent and connections of their fibers, but mor- 

 phologically they may have considerable significance. 



As before mentioned, the cells of the brain are gathered 

 into masses that completely cover the fibrillar substance in cer- 

 tain regions and fill in the spaces between its lobes. Thus the 

 spaces between the optic lobes, the antennal morula and the 

 central cerebral mass are completely filled by them, as is also 

 the deep furrow between the two lateral proto-cerebral lobes 

 on the posterior side of the brain. 



These masses are, with certain exceptions, subdivided into 

 small groups the fibers of which form a bundle in penetrating 

 the central mass. These groups so far as I have been able to 

 distinguish them may be designated by numbers as follows be- 

 low. The most prominent of the exceptions to the rule of the 

 formation of small bundles are the cells about the calices of the 

 mushroom bodies. These are very similar in appearance to the 



