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more resembling in form and attitude those of Ocmis
than those of the typical Cucmnarice, surround the
mouth ; the perisom is th in and semi-transparent,
and the muscular hands, the radial vessels, and
even the internal viscera can he plainly seen through
it. The three arterior amhulacral vessels are approximated,
and on these the tentacular feet are numerous
and well developed, with a sncldng-disk supported hy
a round cribriform calcareous plate, or more frequently
hy several AA'edge-shaped radiating plates
arranged in the form of a ro se tte ; and these three
ambulacra form together, at all eA'ents in the female,
a special amhnlatory surface.
The tAvo amhulacral vessels of the ‘ hivium ’ are
also approximated along the hack, and thus the two
interamhulacral spaces on the sides of the animal,
between the external trivial ambulacra and the ambulacra
of the hivium, are considerably Avider than
the other three ; consequently, in a transverse section,
the amhulacral vessels do not correspond Avith the
angles of a regular pentagon, but with those of an
irregular figure in Avhich three angles are approximated
beneath and tAvo ahove. In the female the
tentacular feet of the dorsal (hivial) ambulacra are
very sh o rt; they are provided with sucking-disks,
hut the calcareous support of the suckers is very
rudimentary, and the tubular processes are not
apparently fitted for locomotion. In the males there
is not so great a difference in character between
the ambulacra of the trivium and those of the
h iv ium ; h u t the tentacles of the latter seem to
1)6 less fully developed in both sexes, and I have
never happened to see an individual of either sex
progressing upon, or adheinng hy, the water-feet of
the dorsal canals.
In a very large proportion of tho females Avhich I
examined, young were closely packed in tAvo continuous
fringes adhering to the Avater-feet of the
dorsal ambulacra (Tig. 38). Tbe young were in all
the later stages of groAvth, and of all sizes from 5 up
to 40 mm. in length ; but all the young attached to
one female appeared to he nearly of the same age and
size. Some of the mothers with older families had
a most grotesque appearance—their bodies entirely
hidden hy the couple of roAvs, of a dozen or so each,
of yellow vesicles like ripe yelloAv plums ranged along
their backs, each surmounted by its expanded croAvn
of oral tentacles ; in the figure the young are represented
ahont half-grown. All the young I examined
were miniatures of their parents ; the only marked
difference was that in the young the ambulacra of the
hivium were quite rudimentary—they Avere externally
represented only hy hands of a someAvhat darker
orange than the rest of the surface, and hy lines of
low papillæ in the young of larger groAvth ; the radial
vessels could he Avell seen through the transparent
hody-wall ; the young attached themselves by the
tentacular feet of the trivial ambulacra, Avhicli are
early and fully developed.
AYe Avere too late at the Ealklands (January 23) to
see the process of the attachment of the young in
their nursery, even if Ave could have arranged to keep
specimens alive under observation. There can be
little doubt that, according to the analogy of the class,
the eggs are impregnated either in the ovarial tube
or immediately after their extrusion, that the first
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