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Remarks. The present genus is very different from any of the pre-
ceding ones, whereas it exhibits some points of affinity to the next genus; and
indeed Rathke combined them in his genus Phryxus. It is now, however, gene-
rally acknowledged that the genus of Rathke comprises 2 distinct generic types,
and the name Pliryxns should accordingly be restricted to one of these types
only, whereas for the other type, the one here treated of, the name Athelges,
proposed by Hesse, ought to be retained. The peculiar contortion of the body
in fully grown female specimens has not yet been sufficiently recognized; for the
species have generally been described as perfectly symmetrical or nearly so, an
appearance which is only exhibited "
by immature specimens. Both in these
and in fully grown specimens, the metasome exhibits several very peculiar
features not found in any of the preceding genera. Firstly, it apparently con-
sists "of only 5 segments, the last of which has the form of a cylindric or clavi-
form piece; secondly, there is no trace of epimeral plates; and thirdly, the pleo-
poda, of which there are only 4 pairs, are extended laterally, and each
consist of a narrow stalk, to which are attached 2 lamella of pronouncedly
branchial structure. The place where the parasite clings to its host, is also very
different from that in the preceding genera. The type of the genus is A.
paguri Rathke,
to be described below. Mr. Hesse has also described several
species from the French coast; but to judge from his figures, only young speci-
mens seem to have come under his notice. One of these is regarded as the type
of a separate genus (Prosthete).
l. Athelges paguri, Rathke.
(PI. Lxxxvni).
Phryxus paguri, H. Rathke, Beitrage zur Fauna Norwegens, in Nova Acta Acad Nat.
t'm-ios. Vol. XX, p. 57, PI. 1, figs. 1315, PI. 2, figs. 11, 12.
Syn. : Bopyrus bernhardi, Kroyer (young).
Athelge fullode, Hesse.
Specific Characters. Body in
Prosthete cannelee, Hesse (young).
Phryxus fusticaudatus, Sp. Bate (young).
fully grown females very asymmetrical,
twisted to one (generally the left) side, and at the same time exhibiting a rather
strong dorsal curvature; anterior division oblong, almost semicylindric, with the
dorsal face concave, the ventral one strongly vaulted. Cephalon oval quadran-
gular, only visible in a dorsal view of the animal. Segments of mesosome well