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235
extremity, undoubtedly represents the alimentary cavity. Dorsally,
at each side
of the latter, a narrow bandlike body tirst makes its appearance, extending
through the greater part of the body, and having its anterior extremity slightly
dilated (see fig. 9 5
)- These bodies are converted in to the ovaries, which in a later
stage (fig.
6
), constitute 2 rather large lobular organs filled with numerous very
small ovicells. In the lateral walls of the body several short muscles are seen
passing from one segment to the next in succession, indicating that the body in
these stages is capable of some slow vermiform movements. All these inner
parts, however, at last wholly disappear, and the body of the fully-grown female is
converted merely into an inert capsule filled with ova or embryos. It often hap-
pens that several young females are found attached to the same Cypridina; but
of these only one becomes fully grown and ovigerous, and it is very probable
that the others soon die off without reaching full maturity. The position of this
parasite in relation to the body of its host is quite contrary to that advanced
by MM. Giard and Bonnier as an unexceptional rule for all Epicarida, the fore-
part of the body always turning the same way as that of the host.
The male is found creeping freely on the body of the Cypridina or on
that of the female (see fig. 9 6
)- It is undistinguishable from the female in the
last larval stage, except by the nature of the generative organs, and it is even
not improbable that, after its function has been accomplished, it becomes con-
verted into a female, and that this form accordingly is protandric in character,
as has been suggested for some other Epicarida.
1
Occurrence. I have not infrequently found this interesting form off the
Lofoten Islands and at Bodo and Selsovig, infesting Cypridina norvegiea Baird,
an Ostracod occurring in great abundance on a muddy bottom in depths varying
from 100 to 300 fathoms. The parasite, when fully developed, is easily obser-
vable through the semipellucid valves of the Cypridina, always occupying the place,
where otherwise the ova and embryos of the latter are carried during their deve-
lopment. Occasionally the parasite also occurs on male Cypridinse but in no
;
instance have I found it in this case fully developed, and it is very probable that
under such circumstances it does not ever reach maturity. Out of Norway this
form has not yet been recorded.