The larvæ in this stage are known, amongst the Balanidæ, in Balanus, Pyrgoma, Coronula, Platylepas, and Chthamalus; and these genera include all the principal forms. Amongst the Verrucidæ they are known in its one genus, Verruca. Amongst the Lepadidæ, in Scalpellum, Ibla, Alcippe, Lepas, Conchoderma, &c.; and in all these genera the larvæ present no important difference--hardly any difference which could be viewed as generic, were these larvæ independent animals,--as may be inferred, chiefly, from Mr. C. S. Bate's descriptions.[51] The abstract given in my former volume was not accompanied by any illustrations, and I have consequently here given (Pl. 29, fig. 8), a view of the larva, in the first stage before moulting, of _Scalpellum vulgare_: the natatory legs are not drawn with accuracy, only the relative position of the several organs having been carefully attended to. I have also had copied from Mr. Bate's memoir, a figure of the larva (Pl. 29, fig. 9) of _Balanus balanoides_, in its first stage, _before_ moulting, with its ventral surface exhibited; and another figure (with a few trifling alterations made after examining specimens most kindly sent me by Mr. Bate) of the larva of _Chthamalus stellatus_ (fig. 10), in its first stage, but _after moulting once_. It should be observed that Mr. Bate has given a drawing of the larva of this latter cirripede, in the first stage, _before moulting_; and it does not differ essentially from that just referred to (fig. 9), of _B. balanoides_, but is rather more fully developed. These drawings suffice to show the character of the larvæ in the first stage, both before and after the first moult, and even after the second moult, throughout the Order of Thoracica. The larvæ sometimes undergo their first moult within the sack of their parent, as I have been informed by Mr. Bate, and as I have observed in Coronula. [51] 'Annals and Magazine of Natural History,' vol. viii (2d series), 1851, Plates 6, 7, and 8.