402 A HISTORY OF RECENT CRUSTACEA 
In the Cryptoniscide the first two segments of the 
pereeon carry very short feet, sometimes degraded, pro- 
vided at the extremity with a strong claw; the pleopods 
are two-branched. ‘The adult female, without becoming 
unsymmetrical, loses the characteristic shape of an Isopod 
and all or most of its appendages. 
The Epicaridea in general pass, according to Giard and 
Bonnier, from the embryo or first stage of their develop- 
ment to a second or cryptoniscian stage, in which they 
resemble the males of this family. According to Dr. 
Fraisse the free-swimming Cryptoniscide have a quite 
peculiar smell, and the female becomes sexually mature 
before adopting a parasitic life. Notwithstanding Pro- 
fessor Kossmann’s scepticism regarding the latter state- 
ment, I believe that it is correct. At all events a minute 
specimen taken in the tropical Atlantic, retaining all its 
appendages, and of the shape usual in the ‘ cryptoniscian 
stage,’ appears to have ovaries crowded with eggs. 
Cryptoniscus, Fritz Miiller, 1864. The characters no- 
ticed by Fritz Miiller are that the young of Cryptoniscus 
are, like most other Isopods, hatched with the last perzeo- 
pods undeveloped, and that the penultimate pair are thin 
and rod-like, differing much from those which precede them. 
Cryptoniscus planarioides, Fritz Miller, 1864, was found 
on Peltogaster purpureus (F. Miiller), together with Phryzus 
resupinatus, on a Pagurid, in Southern Brazil. Fritz 
Miller remarks of this species, that, if the eggs and young 
did not betray the crustacean character, the female would 
almost rather be taken for a flat-worm (a Planarian) than 
for an Isopod. 
The Peltogaster, it must be understood, is a strangely 
metamorphosed Cirripede, which pushes roots into the 
body of its Pagurid host. Then comes the Cryptoniscus, 
penetrates the parasite, and draws nourishment to itself 
through those piratical roots. Strangely it happens next 
that under this infliction the body of the Cirripede, cheated 
of its nutriment, dies and falls away, and yet its roots 
remain and flourish for the benefit of an alien digestive 
apparatus. Crustaceans of three distinct orders are thus 
