r end, but
in the mature Cirripede, the ovarian tubes in the peduncle and the
small, glandular, grape-like masses, near the stomach-caeca, are
connected only by a delicate tube; this I failed in tracing in specimens
in the very immature condition of those now under description.

The larva fixes itself with its sternal surface parallel and close to
the surface of attachment, and the antennae become cemented to it: if the
Cirripede, after its metamorphosis had remained in this position, the
cirri could not have been exserted, or only against the surface of
attachment; but there is a special provision, that the young Cirripede
shall immediately assume its proper position at right angles to the
position which it held whilst within the larva, namely with its
posterior end upwards. This is effected in a singular manner by the
exuviation of the great compound eyes, which we have seen are fastened
to the outer arms of the double = deg.UU deg.=-like, sternal apodemes:
these together with the eyes stretch transversely across, and internally
far up into, the body of the larva; and, as the whole has to be rejected
or moulted, the membrane of the peduncle of the young Cirripede has
necessarily to be formed with a wide and deep inward fold, extending
transversely across it; this when stretched open, after the exuviation
of the larval carapace and apodemes, necessarily causes the sternal side
of the peduncle to be longer than the dorsal, and, as a consequence,
gives to the young Cirripede its normal position, at right angles to
that of the larva when first attached.

* * * * *

I may here state, that I have examined the larvae in this the final or
perfect stage in four species of Lepas, in _Conchodermavirgata_, _Ibla
quadrivalvis_, and, though rather less minutely, in _Balanus
balanoides_, and I find all essential points of organisation similar.
With the exception of diversities in the proportional sizes of the
different parts, and in the patterns on the carapace, the differences,
even in the arrangement of the spines on the limbs and antennae, are less
than I should have anticipated.

I have in this abstract treated the metamorphoses at greater length than
I should otherwise have done, on account of the great importance of
arriving at a correct homological interpretation of the different parts
of the mature animal. In Crustacea, according to the ordinary view,
there are twenty-one segments; of these