230 HISTORY OF BRITISH CRUSTACEA. 



various parts of tlie Irish and Scottish coasts, sometimes 

 associated with an almost equally destructive Crustacean 

 alreadv described, the Chelura. 



Gen. 113. ASELLUS, Geoffr. 



Caudal appendages long. Front legs the largest ; claws 

 simple. Eves small, lateral. Lower antennte of the same 

 length as the bristle- bearing joint of the outer pair. Body 

 oblong, depressed, and deeply divided into nine joints ; one 

 being the head, seven the thorax, and one the abdomen. 



A.SELLUS aquaticus, L. Water Hog-louse. (Plate XII. 

 fig. 6.) — Head large ; inner antennae shorter than peduncle 

 of second pair; peduncle of posterior appendages of abdo- 

 men cylindrical, with two stylets of same length. Six or 

 seven lines long. 



Common in fresh and stagnant water : the male much 

 larger than the female. Its usual walk is slow, but when 

 pursued it can run quickly. 



Gen. 114. <LERA, Leach. 

 Caudal appendages very minute. Front legs not thicker 



