ble
means, which will be most conveniently described in a later part of this
Introduction. I will here only state that I traced with ease the two
cement-ducts running from two large glandular bodies, to within the
antennae up to the discs.

[9] Mr. J. D. Dana, who has examined these organs in the larvae of
Lepas, informs me in a letter, that in his opinion they
"correspond with the inferior antennae, the superior being
wanting, as in most Daphnidae." He continues--"I know of no case
in which the inferior are obsolete when the superior are
developed; but the reverse is often true." In position these
antennae certainly correspond to the inferior and central pair of
the larva in the first stage, which belong, as it would appear,
to the first segment of the body; but judging from the drawing by
Burmeister of the larva in the second stage, I am, in some
respects, more inclined to consider that they correspond to the
larger pair seen within the lateral horns of the carapace in the
first stage.

[10] Rev. B. L. King. Annual Report of B. Institution of
Cornwall, 1848, p. 55.

_Eyes._--Close behind the basal articulations of the antennae, the
sternal surface consists of two approximate, elongated, narrow, flat
pieces, or segments. These Burmeister considers as the basal segments
of the antennae: as they are not cylindrical, I do not see the grounds
for this conclusion: their posterior ends are rounded, and the membrane
forming them is reflected inwards, in the form of two, forked, horny
apodemes, together resembling two letters, =UU=, close together; these
project up, inside the animal, for at least one third of its thickness
from the sternal to the dorsal surface. The two great, almost spherical
eyes in _L. australis_, each 1/150th of an inch in diameter, are
attached to the outer arms, thus, = deg.UU deg.=, in the position of the
two full stops. Hence the eyes are included within the carapace. Each eye
consists of eight or ten lenses, varying in diameter in the same
individual from 1/2000 to 3/2000th of an inch, enclosed in a common
membranous bag or cornea, and thus attached to the outer apodemes. The
lenses are surrounded half way up by a layer of dark pigment-cells. The
nerve does not enter the bluntly-pointed basal end of the common eye,
but on one side of the apodeme. The structure here described is exactly
that found, according to Milne Edwards, in certain crustacea. In
s