the
larvae during their development; it also serves as their nurse, by
allowing the parasites, whilst adhering by their tentacles, to draw
nourishment out of its mouth by means of a large proboscis. In point of
fact, the relation between them is of so unprecedented a nature, that
the author may well be excused for having at first taken the impudent
parasite for the gemmiparous progeny of the sheltering Medusa. The
youngest state of this parasitic Medusa observed by the author formed a
ciliated body of clavate form, adhering to the cavity of the bell by
means of the slender stalk in which it terminated. The first change
consists in the emission, from the thick end, of two slender flexible
tentacles, and in the formation of a central cavity by liquefaction. At
this stage of development, the author frequently observed gemmation
taking place at the thicker end, sometimes frequently repeated.
Subsequently the number of tentacles becomes doubled. These bend
together over the clavate extremity, and are then employed, instead of
the thin end of the body, in adhering to the cavity of the sheltering
Medusa. The thin extremity then acquires a mouth, and may be recognised
as a stomachal peduncle, which is employed, as above indicated, in
obtaining nourishment. The morphological nature of the proboscis becomes
still more distinct when, after the lapse of some little time, an
annular fold makes its appearance immediately under the tentacles, which
is recognisable from its form, and from the formation in it of (eight)
otolithic capsules, as the first indication of the future bell.
Simultaneously with the otolithic capsules, four rudimentary tentacles
make their appearance between the four tentacles. The Medusa remains in
this stage of development for a long time. The bell gradually becomes
more freely developed, and at last, by the reduction and entire
disappearance of the stomachal peduncle, becomes the most essential part
of the Medusa, after it has left its previous dwelling-place in the bell
of the _Turritopsis_. The bell nevertheless retains for some time its
earlier lobed form and unequal tentacles."[231]

More remarkable even than this association is the fact that certain true
Fishes habitually reside in the stomachs of star-fishes. This
circumstance, which had been observed in the Oriental Archipelago by MM.
Quoy and Gaimard, and by Dr Bleeker, has recently been confirmed by Dr
Doleschall, who has written a very interesting M