No. 4-] AMPHITHOE LONGIMANA SMITH. 185 



Sexual Habits. 



Concerning the sexual habits of Amphithoe I have little to 

 add beyond what is known among other amphipods. The male 

 carries the female about for a considerable period and main- 

 tains his hold against efforts to dislodge him with great perti- 

 nacity. The instinct to retain hold of the female is sufficient to 

 overcome all fear, and it is difficult to separate the male without 

 injury. The posterior part of the body may be cut off, and yet 

 the anterior portion retains its hold of the female as long 

 as sufficient vitality remains. Ordinarily the male retains his 

 hold of the female by hooking the claws of his pereopods 

 beneath the edges of the epimera. The gnathopods are not 

 generally employed for this purpose, but are called into use 

 when a sudden disturbance renders the hold of the male inse- 

 cure. The female remains remarkably passive when carried 

 about by the male. Her body is usually held quite strongly 

 flexed and the male does the swimming for both, the female 

 being transported as so much dead weight. While carried by 

 the male the female seems much less responsive to stimuli 

 than when free. When poked by a needle she often makes 

 little motion, but the more alert male is generally aware of the 

 disturbance and carries her away from the seat of annoyance. 



TJie Disposal of Excrement. 



In its natural position Amphithoe lies so that the excrement 

 that is voided would be deposited in the nest. Yet the excre- 

 ment is never found in the nest but at some distance from 

 either end. At first I supposed that it was carried out by the 

 current of water produced by the movement of the pleopods, 

 but, after watching the animal, I noticed that when excrement 

 was extruded the abdomen was bent forward and the gnatho- 

 pods reached back and seized the mass as it was ejected from 

 the intestine, and passed it out of the front end of the nest. 

 This act was observed three or four times, but whether it is 

 always performed when excrement is extruded I cannot state. 

 In one individual lying outside a nest on the bottom of a glass 



