METAMORPHOSES OF CIRRJPEDES. 117 



point, but here lost them. From this same obscure cen- 

 tral part of the disc, in most, if not in all species of the 

 Lepadidse, spokes radiate, which sometimes are branched, 

 and are not regular, not always even resembling each other 

 on the opposite sides of the same individual. Round the 

 proper membranous border of the disc, a second one maybe 

 observed (fig. 8,p), which differs in shape and extent in 

 different specimens : under favorable circumstances, and 

 very high powers, it may be seen to have a reticulated 

 structure, and to be of a very pale brown colour ; towards 

 the exterior margin, the reticulations become finer, and are 

 blended together and lost; on the inner margin, the sub- 

 stance forming this membrane may be seen to come out of 

 the spokes. This substance is the cement, which has the 

 power of adhering to whatever substance it grows against ; 

 and thus the disc of each antenna becomes cemented down, 

 and soon both the antennae are surrounded by a common 

 border of cement, which gradually increases, after the meta- 

 morphosis, in extent. Occasionally the cement forms little 

 projections, like short spines, on the edges opposite to the 

 orifices of the spokes. 



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 seg- 

 ment ; 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 erro- 

 neously stated, in my former volume, that there were three 

 long spines. 



