s; the lowest
posterior filament of the four generally is the largest. In young
specimens, having a capitulum only half an inch long, the upper pair of
the four often is not developed, or is represented by mere knobs. The
mouth presents no distinctive characters. _Cirri_, with the longer ramus
of the first pair almost equal to the shorter arms of the second pair;
spine-bearing surfaces only slightly protuberant. Caudal appendages
smooth, curved, pointed.

_Size._--The largest specimen which I have seen, had a capitulum one
inch and a half in length.

_Colours._--The white valves are edged with bright orange membrane; and
are so close to each other that no interspaces, coloured from the
underlying corium, are left. Peduncle, dark orange-brown, with the
uppermost part under the capitulum bright orange all round; the chitine
membrane itself being thus coloured. Sack, internally, dark purplish
lead-colour. Body and cirri, either nearly white or pale purplish-lead
colour, with the arms of the second, third, and fourth cirri, and
pedicels of the fifth and sixth, more or less tinted with orange. A
specimen preserved during fourteen months in good spirits had only a
tinge of orange left round the orifice and round the upper part of
peduncle, and on the cirri. In some other specimens, badly preserved,
the chitine membrane was quite colourless, and sack and cirri dirty
lead-colour. Fresh ova, peach-blossom-red; immature ova, in ovarian
tubes, pale pink.

_Monstrous Variety._--In Mr. Stutchbury's collection, there was a
specimen, with the scuta, broad, smooth, thin, and fragile, without any
ridge running from the umbo to the apex, and with the occludent margin
reflexed. This seemed caused by the shell having been attacked by some
boring animal, and from having supported Balani. In the same specimen
the first cirrus on one side was monstrously thick and curled; the
second cirrus had its posterior ramus in a rudimentary condition. In Mr.
Cuming's Collection, there are small specimens with the zones of growth
overlapping each other, with thick irregular margins, and with the
carina distorted.

This species has cost me much trouble: I have examined vast numbers of
specimens, from a tenth to half an inch in length, attached to light
floating objects, such as Janthinae and Spirulae from the tropical oceans,
which all resembled each other, and slightly differed from the common
appearance of _L. anserifera_: this variety is the _Pent