118 BALANIDiE. 



In three species of Lepas, in Dichelaspis Warwickii, and 

 in Scalpettum Peronii, after having torn the lately-cemented 

 antennae from the surface of attachment, I observed pro- 

 ceeding from the end of the terminal segment, from be- 

 tween 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 pupae 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 antennae of specimens just attached of Lepas anatifera. 

 In the Dichelaspis and the Scalpelkmi, 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 oft' close to the ex- 

 tremity 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 out- 

 wards and assume definite forms, we know from the singu- 

 lar case of Lepas fascicularis, in which the cement proceeding 

 from several apertures, forms a vesicular float round the pe- 

 duncle 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 that this tube, 

 proceeding from the extremity of the antenna, may be the 

 channel through which cement continues to be poured forth 

 during the continued growth of the above Cirripedes; and 

 the manner in which this is effected, considering how firmly 

 the end of the peduncle is cemented down, has always 

 appeared to me a difficulty. In those pupae of Lepas 

 australis, which I caught swimming about unattached, it is 



