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Bopyroides hippolytes, (Kr0yer).
(PI. LXXXIV, fig. 2).
Bopynis hippolytes, Kreyer, Gronlands Amphipoder, p. 78, PI. 4, fig. 22.
Syn. : Gyge
hippolytes, Sp. Bate & Westw.
Specific Characters. Body of fully grown female broadly oval, rather
asymmetrical, being curved to the right or left, according to its place
on the
host; dorsal face much flattened and very smooth. Cephalon almost semicircular
in form, and deeply immerged within the mesosome, frontal edge nearly straight,
lateral corners obtusely pointed. Segments of mesosome firmly connected, with
the lateral parts perfectly smooth, contiguous, and without any marginal indenta-
tions. Metasome comparatively short, its median length scarcely exceeding 1
/s of
that of the proceeding part of the body, sutures between the segments much
curved and distinct also in the middle of the dorsal face, epimeral plates con-
tiguous, truncate at the tip, last segment likewise truncate. Male very slender,
linear, 4 times as long as it is broad, segments of mesosome very sharply marked
oft' from each other, metasome forming an undivided obtusely conical piece.
Colour of female whitish, with the incubatory plates dark violet. Length of
female reaching to 11 mm., that of male to 272 mm.
Remarks. This form was first described by Kr0yer as Bopynis hippo-
lytes, and was subsequently referred by Sp. Bate and Westwood to the genus
Gyge of Cornalia and Panceri. It must, however, unquestionably find its place
within the genus Bopyroides of Stimpson, and it is indeed somewhat questionable,
if the species of Stimpson, B. acutimarginata, is not identical with the North
European form. In its general appearance and its mode of infesting its host, the
female of this Bopyrid bears a great resemblance to Bopynis squillarum, but may,
on a closer examination, be easily distinguished by the distinct segmentation of
the metasome, and by the want of true pleopoda, the latter being replaced by
very slight, fleshy ridges. The male, moreover, distinguishes itself by its very
slender form and the complete fusion of the segments of the metasome.
Occurrence. I have met with this form along the whole Norwegian
coast, from Vads0 to the ChristianiaFjord. It is found parasitic in the branchial
cavity of 3 different species of the genus Spirontocaris Sp. Bate (Hippolyte
Kr0yer) ; viz., S. polaris, in which species it was first found by Kr0yer, S.
spinus and S. securifrons. I have very carefully compared specimens from all these
3 species, and have not been able to find any difference between them. When