The peduncle is lined within by three layers of muscles, longitudinal, transverse, and oblique, all destitute of the transverse striæ, characteristic of voluntary muscles; they run from the bottom of the peduncle to the base of the capitulum, as in Lepas, or half way up it, as in Conchoderma; in Alepas alone they surround the whole capitulum up to its summit. In Lithotrya there are two little, fan-like, transverse muscles (involuntary), extending from the basal points of the terga to a central line on the under side of the carina. The gentle swaying to and fro movements, and the great power of longitudinal contraction,--movements apparently common, as I infer from facts communicated to me by Mr. Peach, to all the Pedunculata,--are produced by these muscles. The interior of the peduncle is filled up with a great mass of branching ovarian tubes; but in Ibla and Lithotrya, the upper part of the peduncle is occupied by the animal’s body. _Means of Attachment._--If the peduncle be very carefully removed (Tab. IX, fig. 7 and Tab. I, fig. 6 _b_), from the surface of attachment, quite close to the end, but not at the actual apex, the larval prehensile antennæ can always be found: these have been sufficiently described for our present purpose under the head of the Metamorphoses; but I may add, that the diagnostic differences between them in the several genera are briefly given, for a special purpose, in a discussion on the sexes of Scalpellum at the end of that genus. We have seen in the larva, that the cement-ducts, with their opaque cellular contents, can be traced from within the discs of the antennæ to the anterior or lower ends of the two gut-formed bodies, which it can be demonstrated are the incipient ovaria.