Contr. towards the Embryology and Anatomy of Polystes pallipes. 1 < 9 



Gross (10) workiug with Bomhus terrestrls fouud in the distal 

 part of the end Chamber nuclei of the epithelial cells with very 

 iiidistinct bouudaries; these nuclei were oval in shape and contained 

 a few chromatin granules. Further down were large, round cells, 

 with a distinct nucleolus; these were the nurse-cells and between 

 them lay the oöcytes with larger and lighter nuclei. Near the wall 

 were many epithelial cells and he holds that these remain unchanged 

 in structure, and that they divide mitotically at nearly any place. 

 Synapsis, if present, he claimed was very short. In that part of the 

 tubule where the oöcytes have a linear arrangement in its center, 

 they are separated by epithelial cells. Gross holds, against Paulcke (25) 

 that, in this region, the nurse cells do not divide. The egg and nurse 

 Chamber have an opening between them. In the nurse Chambers are 

 a number of epithelial nuclei; these in the older Chambers collect in 

 the central part and pass into the oöcyte: they have something to 

 do with the formation of the deutoplasm. In Vespa he holds that 

 the nurse-cell nuclei may divide amitotically. 



Observations. 



The following paper has nothing to do with the development of 

 the female reproductive organs as such, but only with the cells, oöcyte, 

 nurse, and epithelial, which develop within the ovary. The oöcytes 

 we have traced from their origin, through the formation of the nuclear- 

 like bodies, until they have nearly reached their füll size. Of the 

 nurse-cells the entire history is given; starting from their first 

 differentiation and following them until they become lost, as food for 

 the developing oöcytes. The epithelial cells we have traced from 

 their origin until a part of them, those within the nurse Chamber, 

 have no furtlier history, either going as food to the oöcyte or 

 remaining within the empty Chamber. Of the other part, those 

 forming the foUicle of the oöcyte, we give the history until the 

 beginning of the formation of the chorion. 



It has been thought advisable to draw in outline an ovarian 

 tubule of some of the stages described, not to trace its development, 

 but only that the position of the cells about which we speak, may 

 be more clearly indicated. We begin our account with the gonads 

 of the embryo, finding at this stage, that each reproductive organ is 

 a small mass of protoplasm, surrounded by one or more layers of 

 cells, and containing a number of nuclei similar in structure. In this 

 earliest stage is not only a differentiation into terminal filament, 



