Vv BPICARIDA—LIFE-HISTORY OF BS0PYRUS 133 
caridian and Cryptoniscus stages, a further larval state is assumed, 
called the Bopyrus, which is the functional male, and, after per- 
forming this function, passes on to the adult female condition. 
The family Bopyridae is parasitic in the branchial chamber 
of Decapoda, especially Macrura and Anomura. When one of 
these Decapods is infested with an adult Bopyrid the gill-chamber 
in which it is situated 1s greatly swollen, as shown in Fig. 90. 
A very common Bopyrid is Bopyrus fougerouxt, parasitic in the 
gill- chambers of Palaemon serratus. The Bopyrus larva or 
% 3 
¥ia. 90.—Galathea intermedia, with Fia. 91.—Ventral view of male 
a Pleurocrypta microbranchiata Bopyrus fougerouxt, x 30. 
under its left branchiostegite A, 1st and 2nd antennae ; 
(B), x 1. (After Sars.) 7, 8th (last) thoracic ap- 
pendage. (After Bonnier.) 
functional male has the appearance shown in Fig. 91. It 
differs from the Cryptoniscus stage in possessing a rudimentary 
pair of anterior thoracic lmbs and seven pairs normally 
developed, while the abdominal limbs are plate-like and 
branchial in function. The male can often be found attached 
to the female beneath the last pair of incubatory lamellae. 
The adult female condition, which is assumed after the 
Bopyrid stage is passed through, is illustrated in Fig. 92. 
The body acquires a remarkable asymmetry, due to the unequal 
pressure exerted by the walls of the gill-chamber. The 
antennae and mandibles (Fig. 92, B) are entirely covered up by 
the largely expanded maxillipedes; maxillae are, as usual, entirely 
