19 



When a female is ready to lay a batch of eggs she assumes 

 an upright position and holcis 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 andopods 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 compartment. After tjfie 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 natur- 

 ally supposed to contain eggs that were mature if they were 

 not already fertilized. Before describing the process of 

 fertilization we should consider briefly the structure of the 

 genital organs of the female. 



V. TH3 RfiPRODUGTIVE ORGMS OF THE FEMALE. 



Figure 181 Is a diagramatic representation of the ovary 

 and one seminal receptacle and oviduct of this crab. The 

 ovary is an H shaped tube, the lumen of which opens directly 



