The cellular elements of the Ovary of Platyphylax designatus Walk. 217 



Any tubule (Fig. 1) from ovary A shows distally a well formed 

 terminal filament, the cells of which, except at its very tip, are 

 elongated and lie across tlie filament Leydig '24), Paulcke (28). 

 The nuclei within these cells are also much elongated; each contains 

 a small nucleolas and a niimber of chromatin grannies which are 

 connected by achromatin Strands (Fig. 2). Following the terminal 

 filament is a large Chamber, oval in outline, in which cells are found 

 in different stages of development. These Chambers dififer somewhat 

 in shape, due to the pressure of the neighboring ones, and we find 

 them long and narrow, or shorter and thicker. Along the margin 

 lie most of the smallest cells; they may show an epithelial -like 

 arrangement, or, in many tubules, this may to a great extent be 

 lost. It is not true that all marginal cells are small and have small 

 nuclei, for we find, here and there, some on the margin as large as 

 any in the central part of the Chamber (Fig. 4 c). Töxniges (37) 

 has found that in Myriopods some of the epithelial cells of the wall 

 of the ovary, grow to form undifferentiated cells, which may later 

 develop to oöcytes, nurse- or follicle cells. Proximal to this Chamber 

 is a stalk which connects it to the long oviduct common to all the 

 tubules of each ovary. In this early stage the stalk has a small 

 lumen but the oviduct itself (Fig. 1 odt] is still solid. Of these latter 

 parts no further notice will be taken, this account being confined 

 entirely to the cells which lie between the terminal filament and the 

 basal stalk, and from which develop the oöcytes, nurse- and epi- 

 thelial cells. In both the stalk of the tubule and the oviduct there 

 are many mitotic figures. 



From this ovary, A, we shall select two tubules, one of the 

 youngest (Fig. 1) and one of the oldest (Fig. 8), and describe the 

 different kinds of nuclei the cells in each contain. In most, but not 

 all, of the sections through any of the tubules are a few mitotic 

 figures; they may occur in any part but are more numerous near 

 the margin. 



In the youngest tubule (Fig. 1) are a number of cells with nuclei 

 showing different structures but there are not so many kinds as will 

 be found in later stages. In the distal region we find the greatest 

 amount of similarity in their structure, but even here the cells differ 

 much in size and also in the contents of their nuclei. Some of the 

 cells lying at this region along the margin show, from their nuclear 

 structure, a great similarity to the cells of the terminal filament; 

 these represent the youngest stage. In Polistes we have shown that 



