240 F. E. CHIDESTER. 



Experiments were made \\itli males of the three species under 

 consideration by placing with them females of the same species 

 known to be fcrtili/ed and to have protruding plugs. In no case 

 was a in. ilc successful in his attempts to copulate. In the case 

 of one rock crab, the female was beaten into submission and the 

 male succeeded in touching the plugs. The discomfort caused 

 -4ie -li violent struggles on the part of the female that she was 

 released. 



The female rock crab with eggs was placed with a male 1 of the 

 same Aperies, but his efforts to overcome her resistance were 

 futile. In neither the fertilized and spermatophore plug-bearing 

 female, or the egg-bearing female is a true passive state produced 

 by the beating of the chelae and ambulatory appendages of the 

 male. 



In the case of a large male and a small female, the adjustment 

 of the abdomens is very difficult. In the case of one large male 

 it was noted that the adjustment was not possible in the normal 

 position, and that he turned upon his back so that the female 

 floated above him and her abdomen was extended to a greater 

 degree. Then he slowly drew her into position, and having in- 

 serted his verges, assumed the normal position above her. In 

 all of the species studied, the female is not passive in the later 

 stages of adjustment, but uses her ambulatory appendages to 

 assist in the turning of her body. I should have liked to place 

 a soft-shelled male with a male that had just been separated from 

 .1 -.oft female, but was not able to do so. 



3. MATIN* ; HABITS OF OTHER ARTHROPODA. 

 ('rn.^tiK'i'a. Herrick did not study the mating habits of the 

 lobster i in i but noted the fact that there were external seminal 

 pouches in the female. He states that the copulation is inde- 

 pendent of the moulting of the female. I lerrick mentions the dis- 

 covery by Milne-Edwards of a female ('inner (xi^ints which was 

 fcrtili/ed and in which \\cre \\liat M ilue-Kdwards at first look 

 to be the wands of the male, broken off after copulation as in the 

 insects. Later, Milne-Edwards said in reference to this observa- 

 tion that it seemed probable that the stoppers found in the 

 copulating poncho of t he female were "of the nature of spermato- 

 phores rather than a fragment of tin penis." 



