162 RAYMOND BINFORD 
When a female is ready to lay a batch of eggs she assumes 
an upright position and holds the abdomen out from her body 
so that it and the exopods of the abdominal appendages form 
a basket into which the eggs are run. They there become at- 
tached to the hairs of the endopods of the appendages and pass 
through the embryonic stages of their development, which requires 
from nine to thirteen days. The eggs then hatch and the larvae 
escape. The female then cleans off the egg-shells and their 
stalks from the hairs of the pleopods and, after one day to three 
weeks, she spawns again. Eight days is a very common length 
for the period between the hatching of one batch of eggs and the 
spawning of the next. With these facts in mind I made a large 
floating cage with fifty compartments and collected a large 
number of females with eggs and placed one in each compart- 
ment. After the eggs of several of these had hatched so that 
there were some fifteen crabs without eggs I kept these under 
almost constant observation, day and night. When one assumed 
the position ready for spawning it was naturally supposed to 
contain eggs which were mature if they were not already fertil- 
ized. Before describing the process of fertilization we should 
consider briefly the structure of the genital organs of the female. 
5. THE REPRODUCTIVE ORGANS OF THE FEMALE 
Figure 121 is a diagrammatic representation of the ovary and 
one seminal receptacle and oviduct of this éGrab. The ovary is 
an H-shaped tube, the lumen of which opens directly into the 
seminal receptacle at a point a little posterior to the cross con- 
nection of the H. The eggs are produced in the wall of this 
tube and when mature are set free in the lumen. 
The seminal receptacle is composed of two parts, a glandular 
portion (figs. 121 and 122, g.) into which the ovary opens and a 
portion lined with chitin (figs. 121 and 122, c.) from which the 
oviduct leads to the third segment of the sternum. ‘The sper- 
matophores are stored in the latter division. The cavities of 
the two portions communicate through a large opening (fig. 
121, 0.) in the chitinous lining. Just before the crab molts, the 
glandular portion secretes a mass of gelatinous material which 
