Kenyon, The Brain of the Bee. 151 



characteristic of — especially the higher — hexapods. Special 

 swellings found on the brains of certain of the Crustacea 

 have been compared with them, but it is to be seriously doubted, 

 I think, whether such swellings or cellular heaps are properly 

 to be homologized directly with them. In neither Retzius' 

 (90) figure of the brain of Astaciis fluviatilis nor in Bethe's fig- 

 ures of the brain of Carcinus mceniis can I find cells having the 

 relations and the appearance of those that I find in the 

 bee. I have noticed nothing resembling the structures in 

 isopods, or amphipods, nor I have found indications of them in 

 the brains of Patiropits, Poly xe mis, juloid diplopods, Scolo- 

 pciidrclla, Liihobhis, nor even in several forms of TJiysanura 

 that I have examined. If cells homologous with those filling 

 the cup-like calyx of the mushroom bodies of the bee are at all 

 present in these forms, they are so undifferentiated as to be in- 

 distinguishable from the general mass of cells about them. 



TJie Calyx-Ctip. 



The four bodies that in the bee and the Hymenoptera in 

 general constitute what may be called the calyx-cup form the 

 upper portion of the proto-cerebron, and are arranged side by 

 side, a pair to each lateral lobe. In section, as shown in the 

 photographs of Plates XIV and XV and in optical section in 

 transparent unsectioned preparations, they are very noticeable 

 from the curved masses of fibrillar substance that form the base 

 and walls or calyx of each making them resemble optical sections 

 of so many cups. Each cup holds a mass of cells that fill it to 

 the brim. The walls of each lateral pair are nearly or quite 

 contiguous, except distally where they diverge from one another 

 leaving a space filled with a mass of small cells, as is also the 

 space between each outer cup and the inner fibrillar mass of 

 each optic lobe. Viewed from above they would appear elon- 

 gated antero-posteriorly or with their included cells as four folds 

 along the top of the brain, each extending backwards and in- 

 wards toward the median line. The inner one of each pair is 

 broadest anteriorly and somewhat overlaps its outer mate or 

 appears to crowd it back. On the other hand the outer one is 



