408 A HISTORY OF RECENT CRUSTACEA 
(Pennant) (see Plate XVIII.). The specimens found were 
in about one per cent. of the crabs examined. 
Portunion Salvatoris (Kossmann, 1881), on Portunus 
arcuatus, Leach. 
Portunion Monezu, Giard (1878), on Portunus iba 
(Linn.). Excessively rare. 
Portunion Fraissei, Giard and Bonnier, 1886, on Por- 
tunus holsatus, Fabricius. 
Portunion Kossmanni, Giard and Bonnier, 1886 (see 
Plate XVIIT.), on Platyonichus latipes (Pennant). 
This is the only species that can be called common, 
and one which does not necessarily sterilise the host or 
hinder the exuviation of its integument. These are pro- 
bably the conditions that have allowed it to become 
-common, since, when the parasite makes the host sterile, 
it, so to speak, cuts the ground from under its own feet, 
by preventing the propagation of the very animal which 
is essential to the existence of the parasites own progeny. 
Pinnotherion, Giard and Bonnier, 1889. Parasitic on 
Pinnotheres. ‘The first marsupial plate is without a trans- 
verse lamella, and its recurrent part is of unusual length. 
There are no dorsal ovarian humps, but of the ventral two 
the hinder is excessively long and cylindrical, with 
vermiform movements, whence the type species is called 
Pinnotherion vermiforme. 
Family 7.—Dopyride. 
The animals are parasitic in the branchial cavity, with 
a few exceptions. The females in general have a flattened 
appearance with one side longer than the other. Guard 
and Bonnier, as already mentioned, subdivide this family 
into Phryziens chiefly found on Macrura Anomala, Loniens 
on Brachyura, and Bopyriens on regular Macrura. In 
the Bopyriens the pleon is very degraded in both sexes, in 
the male a single piece without appendages, in the female 
shorter than in the Joniens and never carrying ramified 
appendages. These latter on the other hand are the rule 
in the loniens, of which moreover the males sometimes 
—"? 
