caudal appendages, p. 43; alimentary canal, 44; circulatory
system, p. 46; nervous system, ib.; eyes, p. 49; olfactory
organs, p. 52; acoustic(?) organs, p. 53; male sexual organs, p.
55; female organs, p. 56; ovigerous lamellae, p. 58; ovigerous
fraena, ib.; exuviation, p. 61; rate of growth, ib.; size, ib.;
affinities of family, p. 64; range and habitats, p. 65;
geological history, p. 66.

[3] The meaning of this and all other terms is given in the
Introduction, at pp. 3-7.

_Metamorphoses._--I will here briefly describe the Metamorphoses, as far
as known, common to all Cirripedia, but more especially in relation to
the present family. I may premise, that since Vaughan Thompson's capital
discovery of the larvae in the last stage of development in Balanus, much
has been done on this subject: this same author subsequently
published[4] in the 'Philosophical Transactions,' an account of the
larvae of Lepas and Conchoderma (Cineras) in the first stage; and seeing
how totally distinct they were from the larva of the latter stage in
Balanus, he erroneously attributed the difference to the difference in
the two families, instead of to the stage of development. Burmeister[5]
first showed, and the discovery is an important one, that in Lepas the
larvae pass through two totally different stages. This has subsequently
been proved by implication to be the case in Balanus, by Goodsir,[6] who
has given excellent drawings of the larva in the first stage; and quite
lately, Mr. C. Spence Bate, of Swansea, has made other detailed
observations and drawings of the larvae of five species in this same
early stage, and has most kindly permitted me to quote from his
unpublished paper[7]. I am enabled to confirm and generalise these
observations, in all the Cirripedes in the Order containing the Balanidae
and Lepadidae.

[4] Philosophical Transactions, 1835, p. 355, Pl. vi.

[5] Beitraege zur Naturgeschichte der Rankenfuesser, 1834. Mr. J.
E. Gray, however, briefly described, in 1833, (Proceedings,
Zoological Society, October,) the larva in the first stage of
Balanus; in this notice the anterior end of the larva is
described as the posterior.

[6] Edinburgh New Philosophical Journal, July 1843, Pls. iii and
iv.

[7] This will appear in the October number (1851) of the 'Annals
of Natural History.'

The ova, and consequently the larvae of the Lepadidae, in the _First
Stage_,