958 BOPYRIDA. 
seven segments of the body is furnished with a pair of legs, 
affixed within the lateral margin on the underside; they 
are more elongated than in the Bopyri, and more or less 
hooked for prehension; they are nearly uniform in size, 
the anterior pair being, however, the strongest, and the 
posterior the longest and most slender in one or more of 
the species.* 
" Each of the segments of the tail is furnished on the 
underside with a pair of branchial appendages differing 
in form in the different species, but very strongly fringed 
with long sete. 
The female is a large inert mass of animal matter, 
destitute of appendages, and is affixed to the animal on 
which it is parasitic. It is divided into two portions, the 
one consisting, according to Lilljeborg, of four distinct 
segments, which supports the organ or tube by which it 
adheres to its prey, whilst the hind part of the body 
consists of a simple sac for holding the eggs. 
Writing to us on this genus, Dr. Fritz Miller says, 
‘* Changes in form not less important than those observed 
in the Hyperina are to be seen also in the Bopyride. I 
have already published the description of a new genus 
of this family, Entoniscus, whose retrograde metamor-— 
phosis proceeds much farther than that of Bopyrus (see 
p- 265 post, note +). Ihave since found another species 
of the same genus living in different Brachyura (Xantho, 
&c.), and a second genus (Cryptoniscus, F. Miller, 
MSS.), almost unrecognizable when adult; indeed the 
female of it then resembles Planaria lactea rather than 
an Isopod. It is, moreover, very interesting in its habits ; 
it does not take its sustenance directly from the little 
Pagurus, on whom it is fixed, but from the roots of the 
“In the species observed by Lilljeborg and Fritz Miiller (Zntoniscus 
Galathee) the young have only six pairs of legs. 
