36 T. KOMAl : S TUDIES OX TWO AlJliKRANT CTENOPHORES 



It presents no feature characteristic of tlie form in any respect. As 

 shown in PI. 5, fig. 7, each ovarial tract is made up of numerous 

 developing egg-cells scattered with some glandular cells. Of the egg- 

 cells, naturally of various sizes according to the stage of development, 

 the large ones are situated, as a rule, close to the cavity of the canal 

 and the smaller ones outside of the former in the order of sizes. The 

 eggs which have arrived at their full development in the ovary, have a 

 structure characteristic of the ctenophoran egg, consisting of two plasmic 

 layers distinguishable from each other, one confined to a small extent of 

 the superficial parts and granular in appearance, and the other occupying 

 all the remaining parts and presenting an alveolar structure. The nucleus 

 is imbedded somewhere in the outer layer and may measure some 20 fi in 

 diameter. The small egg-cells are generally polygonal in form, apparently 

 owing to mutual pressure. They contain a vesicular nucleus which 

 is very large in size relatively to the size of the cell and has its 

 chromatin substance often divided into some clumps of subequal sizes. 

 The nucleolus is also large and spherical in shape. 



The spaces among the egg-cells are occupied by the glandular 

 cells, as also the space between the egg-cell mass and the ovarial 

 membrane to be directly described. Of the glandular cells, one can 

 distinguish two kinds, the granular and the clear, each resembling 

 closely the two kinds of gland cells occurring in the epidermis dealt 

 with above. The granular cells (g: £-), which are by far the commoner 

 of the two, contain small secretor\- spherules staining very actively with 

 eosin or iron-haematoxylin. The clear cells (c. o) are scattered among 

 the former, but they occur more commonly in the external parts of the 

 ovary, quite close to the membrane. They take up haematoxylin fairly 

 well. 



The ovary is defined from the surrounding body parenchyme b>' a 

 membrane appearing very similar to the testicular membrane (fig. 7, ii; 

 ov. m). The membrane may become extremely thin like the testicular 

 membrane, in fact even to such an extent that it shows an. almost 

 structureless appearance, although revealing its flattened nuclei here and 

 there by closer examination at any time. 



At the outset of the development of the ovary, small egg-cells 

 make their appearance in small clumps between the endodermal cells of 

 the canal wall (PI. 5, figs. 9, 11). They are at that stage very hard to 

 distinguish from the .spermatogonia, excepting for the difference in 

 situation. The ovarial membrane seems to differentiate from some of the 



