MQIDM. 275 



Samouelle into his work on British Insects, without, how- 

 ever, any locality being subjoined, and, as it is omitted by 

 Mr. White in his Catalogues of the British Crustacea, 

 it seems evident that no tradition exists in the British 

 Museum (of which Mr. Samouelle was also an officer) 

 to warrant its introduction. As it is possible, however, 

 that it or some other of these fish-parasites may occur, 

 we have introduced the above family characters. 



In the second tribe of Milne Edwards, forming our 

 Fam. 



The species are amongst the largest known Isopods, 

 and are distinguished by having their antennae fixed 

 in front of the head, the basal joint of the anterior pair 

 being very broad and flat, and uniting together to form 

 a margin in front of the head, not being concealed 

 beneath the advanced cephalon ; the outer-foot jaws 

 have the basal joints moderately dilated, with three 

 or four terminal joints, which are rarely palpiform ; the 

 pereiopoda are of moderate length, the anterior pair 

 being generally the strongest and fitted for prehension, 

 being terminated by a robust curved finger, acute at the 

 tip; whilst the hind legs are gradually elongated and 

 fitted for walking. The five segments of the pleon are 

 very short, each on its underside supporting a pair of 

 double foliaceous plates for respiration, whilst the last 

 segment of the pleon is large and flat, and bears on each 

 side near the base a pair of flat appendages, scales arising 

 from a basal joint, of which the inner angle is sometimes 

 produced into a long style. 



T 2 



