548 E. W. SEXTON AND ANNIE MATTHEWS. 



was from 4°-10° C. during the same period. In order to test the 

 difference, if any, in the rate of moulting, a brood was divided, half 

 being kept in the Laboratory and half in the other room, and it was 

 found that some of the young took twice as long over their first moult 

 in the colder place — in fact, some of those in the Laboratory had 

 accomplished a second moult before all the young in the other room 

 had finished their first. 



The main food is ulva, supplemented by enteromorpha, and the 

 rotting leaves of oak, beech, and sycamore. Certain kinds of animal 

 food are eagerly taken, such as Siihaeroma serratitm from the ditches in 

 all stages of putrefaction, but this is a diet we give sparingly for fear 

 of fouling the water. 



Occasionally healthy males will attack and devour weak or sickly 

 females, but they have not been seen eating dead ones. The animals 

 will tear up their cast skins or " moults," and if these are not 

 removed within, say, twenty-four hours, they will disappear com- 

 pletely. The inference is that they are eaten, and we feel sure this 

 inference is correct, although we have no direct proof. It is certainly 

 the case in other genera — two Jassa, for instance, were actually 

 watched in the Laboratory devouring their skins immediately after 

 ecdysis ; and again, we have never found any torn pieces of a moult 

 that has disappeared in the dirt pipetted daily out of the bowls. 



Both male and female feed during the carrying period of the mating 

 — not only cropping the ulva while resting on it, but holding pieces with 

 their gnathopods while swimming. The young feed while in the 

 incubatory pouch ; their intestines are full when they emerge. 



EEPRODUCTION. 



The conclusions arrived at by Holmes (3) and Embody (2) on the 

 mating of Amphipods are, as we understand, as follows: — (1) that 

 neither sight nor smell is concerned in the mating of a pair ; (2) that 

 they meet accidentally ; and (3) that the female is wholly passive 

 throughout, and indeed that the male recognizes her as a female by 

 this passivity. Our results, as far as we have gone, indicate on the 

 contrary that mating is not one-sided but mutual, and that a female 

 when in the right physiological condition will at times seek the male, 

 and, on the other hand, when not in this condition will actively resist 

 him. The meeting of the sexes in the first place seems accidental, but 

 the one certainly appreciates the presence of the other by the touching 

 of the antennae. The antennae are provided with highly developed 

 sensory organs, in which the olfactory sense may or may not be 



