LIFE-HISTORY AND HABITS OF TERRESTRIAL ISOPODA 305 



be put in water it at once commences a rhythmic opening 

 and closing of the abdominal appendages, which is distinctly 

 gill-like ; further, if the specimens be rather deeply anaesthe- 

 tised with chloroform before immersion, this movement is 

 carried on during anaesthesia. The effects of the chloroform 

 pass off firstly in the front portions of the body. 



"In water, specimens frequently walk backwards, and as 

 frequently keep the abdomen turned upwards, nearly at 

 right angles to the body. Apparently this is an attempt to 

 reach the upper air." He further states that " when removed 

 from water, the movement of the abdominal appendages 

 ceases." This, however, I have found to be the case only after 

 some of the surplus moisture has been got rid of. 



In captivity very little movement takes place in any 

 species during the morning, unless a ray of sunshine happens 

 to fall across the cells. Specimens of Porcellio scaber marked 

 with different patterns in white paint, were found to regularly 

 return to the same resting place. During the spring and 

 early summer they commence to move about as soon as ever 

 the light fades, becoming more active as the darkness 

 increases. 



A very characteristic attitude of P. scaber is on the corner 

 of a broken piece of a flower-pot, with one of the antennae 

 raised and elbowed, as if in the act of listening. The 

 antennae are used for many purposes. I have watched a 

 male P. scaber stroking the antenna of the female as follows : 

 after taking up a position at her side and slightly in front, 

 the right antenna of the male commences to touch that of 

 the female. After two or three taps, the movement develops 

 into a distinct stroking action commencing from the base 

 of the female's antenna to the tip. At first the movement is 

 slow, but later becomes much more rapid. 



The antennae are cleaned with the aid of the first pair of 

 walking legs, which are provided with a series of spines on 

 the terminal joint which function as a comb, and a further 

 series on the anterior surface of the next joint Mr Aubin 

 describes the use of this cleaning apparatus in Porcellio Iccvis 

 as follows: — It is used in three different ways: (i) the 

 flagellum of the antenna is grasped between the comb 

 46 2K 



