222 BUMPUS. [Vol. V. 



and between the older. If the walls of an ovary at this stage 

 are cut with a pair of scissors, the egg-cells, old and young, 

 ooze from the opening, though held together by the connective 

 and epithelial tissue of the interior of the organ. The mature 

 cells present the appearance of a bunch of grapes, while the 

 young appear as small white patches. 



If the ovary, slit open, is allowed to remain for a few hours in 

 weak acid, additional features are brought out. The mature 

 egg-cells become bright red, while the young cells assume an 

 opaque white color. The distal portion of the mature eggs, 

 however, is lighter in shade, and perhaps contains more proto- 

 plasm than the smaller, tapering, proximal ends where the 

 enveloping tissue acts as a stem or peduncle. 



If the enveloping tissue, the follicular membrane, is carefully 

 ruptured by the use of needles, the enclosed egg will drop out. 

 This egg is surrounded by a definite structureless membrane 

 which in places, in prepared specimens, will be found to stand 

 off in blisters from the enclosed yolk, and after brief macera- 

 tion in water will swell up to twice its normal size, leaving the 

 yolk, within, a naked ball. 



Eggs having the above-described membrane, which, with Ishi- 

 kawa, I may call the "primary egg membrane," were sometimes 

 found lying free in the ovaries of the females that had recently 

 deposited their eggs. 



Such mature eggs as have been dropped from their follicles 

 into the lumen of the ovary, before extrusion, are more or less 

 irregular from mutual pressure, and cling together in masses, 

 not, evidently, from the presence of any specially sticky fluid, 

 but rather from a natural cohesion. 



While the eggs are passing through the oviduct, they are 

 probably covered with a varnish-like coat secreted by the elon- 

 gated cells of the columnar epithelium. This coat adheres to 

 the primary membrane, renders it more impervious to water, 

 and also forms the funiculus by which the eggs are attached to 

 the hairs of the lower side of the abdomen and swimmerets. 



Let us now examine a section of a more mature ovary, a fig- 

 ure of a portion of which is shown in PI. XVI, Fig. II. It is 

 drawn on the same scale as the much younger Fig. 12. The 

 organ has a diameter of nearly ten times that of the young ovary 

 described above. The enveloping walls are much thicker, and 



