is also attached, and so on to all the lower ones;
but I believe no cement tissue continues to pass out through these
lower apertures. Beneath the lowest aperture the two ducts run into the
two prehensile antennae of the larva, which, as usual, terminate the
peduncle. The antennae are attached to some small foreign body in the
centre of the vesicular ball, by the usual tough, light brown,
transparent cement. The two upper apertures are nearly on a level with
the outside surface of the ball; and it was evident that as the animal
grows, new apertures are formed higher and higher up on the sides of the
peduncle, and that out of these, fresh vesicular membrane proceeds, and
grows over the old ball in a continuous layer. It appears that the
growth of the vesicular ball is not regular,--that it is not always
formed,--and that when formed the whole, or the lower part, sometimes
disintegrates and is washed away. As that portion of the peduncle which
is enclosed ceases to grow, and has its muscles absorbed, retaining only
the underlying corium, whereas the upper unenclosed portion, and
likewise, (as it appears) lower portions once enclosed but since
denuded, continue to increase in diameter, the peduncle, when the
vesicular ball is removed, often has the most irregular outline,
contracting suddenly into a mere thread, and then occasionally expanding
again at the basal point.

Frequently two or three specimens have their peduncles imbedded in one
common ball, of which there is a fine specimen in the College of
Surgeons (Pl. I, fig. 6), the ball being about one inch and a quarter in
diameter, with a slice cut off. In this specimen, it is seen that the
vesicular membrane proceeding from several individuals, unites to form
one more or less symmetrical whole, and that the original common object
of attachment is entirely hidden. Dr. Coates[29] gives a curious account
of the infinite number of specimens, through which he sailed during
several days, in the Southern Atlantic Ocean: the balls appeared like
bird's eggs, and were mistaken for some fucus, which was supposed to
have encrusted the scales of the Velellae, to which the Cirripede had
originally become attached. Several individuals had their peduncles
imbedded in the same ball, "which floated like a cork on the water." As
this species grows into an unusually bulky animal, we here see a
beautiful and unique contrivance, in the cement forming a vesicular
membranous mass, serving as