66 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Homarus americanus , as described by Professor Bumpus. ( Jour- 

 nal of Morphology, V, 1891. ) 



"5. The well-known hook on the ischiopodite of the third 

 walking leg of the male is used in the process of conjugation to 

 firmly attach the male to the female. The tip of the hook de- 

 presses the membrane between the coxopodite and basiopodite 

 of the fourth walking leg of the female, and the hook catches 

 firmly against a stiff ridge on the basiopodite. 



*'6. The sperm is conveyed down the groove of the stylet or 

 first pleopod of the male from the penis-like everted end of the 

 vas deferens into the cavity of the annulus of the female. The 

 annulus becomes filled and a plug of sperm and protective se- 

 cretion projects from the orifice after conjugation. 



"7. At a definite stage in the process, the male always passes 

 either the right or left fifth, or last, walking leg across under 

 the thorax so that it projects horizontally from the other side. 

 The limb then holds the first and second pleopods, the intro- 

 mittent apparatus, depressed at an angle of more than forty-five 

 degrees from the ventral surface of the male, and this insures 

 their entrance into the annulus when the male moves forward 

 over the female. 



"8. During the process the ventral sides of the two animals 

 are closely applied to one another and the abdomen of the male 

 partly encloses the abdomen of the female. The latter lies on 

 the back or partly on one side and is firmly held by the large 

 chelte of the male which grasps all the chelate appendages of 

 the female. 



"9. There is no wide distribution of sperm as has been de- 

 scribed for Astacus; it is all placed in the annulus. The ovi- 

 ducts of the female are not concerned in the process of conju- 

 gation. 



"In the one case in which eggs were laid in captivity, the 

 nervous system of the female was very irritable for several days. 

 During the time, by assiduous labor with both of the fifth 

 walking legs, she carefully removed all foreign matter from the 

 ventral surface of the abdomen and from the pleopods. 



"The sperm plug remained in the annulus for two days after 

 the eggs were laid and then disappeared. It was probably re- 

 moved by the female. The process was, however, abnormal 

 and the eggs did not develop." 



