76
THE ESSEX NATURALIST.
evidence is not perfect, and he sincerely hopes that some English-
man may be found with time, perseverance, opportunity and
capacity to undertake the prolonged task (at least three years)
of dealing anew with the metamorphoses of this very delicate
and trying form, and recording in writing, with sketches and
photographic records, the life history in close detail of this
creature. Reliable cultures would be welcomed by the Curator
of the Coelenterata Section of the Natural History Museum at
South Kensington, and every assistance possible would be
given to a serious worker. Hydra Tubae are fairly easily kept.
They do not require highly oxygenated water except during
the period of strobilation, when if success is desired there must
be a high content of oxygen in the. water. They are seen to the
greatest advantage in quite stagnant water, and since putrid
nereids are a "bonne bouche" it will be realised that a nitro-
genous condition of the water is endured well by them, unless,
of course, it is very bad indeed. Containers may be square or
round and not less than one gallon in content; a little weed,
Enteromorpha (if sunny) Ulva (if shady), carefully examined pre-
viously for strangers, is helpful. The best bottom is small
stones, coarse sand, and comminuted cockle shells mixed. If
the air is sweet it is unnecessary to change the water frequently,
but "specific gravity bubbles" should be used often, especially
in summer, and evaporation made up gently. Even changes
of sea water should be gradual and free access to the air is
essential. Growth of vegetation on the glass is rather helpful
than otherwise and encourages Foraminifera, the young forms
of which, together with infusorians, provide food. My Type 2
(pink) lived for five years in the same gallon jar on a mantelpiece
away from the light and with but a faint current of air ; there
were no weeds, but only slight growths of algae on the glass, on
which also lived and reproduced the Foraminifer Spirilina, the
infusorian Folliculina ampulla and other infusoria. Turbellarian
worms (Convoluta) were sometimes present. The Hydra Tubae
themselves were artificially fed on the small (2 in. or 11/2 in.)
"ruddy brown" garden worm with an orange tip and a rather
persistent odour (Dendroboena subrubicunda), found in damp and
wet situations. The Hydra tubae in this case lived well and
produced magnificent red strobilae. Chrysaora likewise
developed well once babyhood was past, on garden worm food. I