THE ISOPODA 



217 



including members of the same sub-order, Amphipoda,Euphausiacea, 

 Decapoda). In both groups the parasitic habit is associated with 

 the occurrence of hermaphroditism. The Cymothoidae present a 

 series leading from the predatory, actively swimming Cirolaninae, 

 with mouth-parts adapted for biting, to the sedentary Cymothoinae, 

 with suctorial mouth-parts. Some of the Epicaridea (Entoniscidae) 

 become practically endoparasitic, penetrating into the body of the 

 host, although remaining enveloped by an invagination of the 



Fir.. 131. 



Bathynomus gigantcu*, dorsal view, alxjut three-sevenths of natural size. 

 (After Milne-Edwards and Bouvier.) 



integument. The mode of absorbing nutriment by root -like 

 processes penetrating the body of the host, which is found in 

 the Rhizocephala and some Copepoda, appears to be adopted by 

 some of the Liriopsidae. 



Some of the smallest Isopoda are found among the Asellota, 

 certain species of which do not exceed 1J mm. in length when 

 adult. A length of three inches is exceptional in the Order, and 

 Bathynomm giganteus (Fig. 131), which reaches nearly eleven inches 



