The small terminal segment usually bears on its truncated extremity six spines, some of which are occasionally hooked; in Scalpellum, two spines, rather longer than the others, are borne on a step some way down on the inner side of this segment; but in Lepas, two spines (fig. 8), very much longer than the others, arise from the outer corner of the extremity. These two are very different from the other four borne by this segment, or indeed any other spines on the body; for they are quite flexible, and are furnished with a double row of very long, straight, excessively fine hairs, which seem to be articulated on them--the whole presenting a very beautiful appearance. These spines are of considerable length, and in _Conchoderma virgata_ they even equal in length the whole antenna. I can hardly doubt that these beautiful, plumose, flexible spines, into the thick bases of which the coloured corium could sometimes be seen to enter, serve as feelers. Owing to the facts immediately to be mentioned, I erroneously stated, in my former volume, that there were three long spines. In three species of Lepas, in _Dichelaspis Warwickii_, and in _Scalpellum Peronii_, after having torn the lately-cemented antennæ from the surface of attachment, I observed proceeding from the end of the terminal segment, from between the above two groups of spines, what appeared to be a long narrow ribbon with its end torn off; and which, in the case of _Lepas australis_, I fancied was one of the plumose, long, flexible spines ripped open. But now that I have examined some of the pupæ of this species before their attachment, I find (as represented in Pl. 30, fig. 8, _v′_) a flattened tube, ending in a blunt point, and having a peculiar ringed structure. I have noticed similar appendages to the antennæ of specimens just attached of _Lepas anatifera_. In the Dichelaspis and the Scalpellum, the tube was very long, and seemed, from its torn appearance, to have been firmly attached to the supporting surface. In both these cases, the tube came out from within another slightly larger tube, which had been broken off close to the extremity of the terminal segment of the antenna. In the case of the _Lepas anatifera_, the tube expanded a little after leaving the antenna. In the Dichelaspis, it had exactly the same diameter as the cement-duct, which could be clearly distinguished within the two lower segments. From these several facts, and from the peculiar appearance of the tube itself, I believe it to be a tube of cement-tissue which thus, sometimes even before the pupa is attached, independently grows outwards. That the cement-tissue can grow outwards and assume definite forms, we know from the singular case of _Lepas fascicularis_, in which the cement proceeding from several apertures, forms a vesicular float round the peduncle of not only a single individual, but often of a group of specimens: we shall presently find a somewhat analogous fact in the case of Coronula. It is possible