SUBCLASS III. 



CIRRIPEDIA. 



■. li 





The relations of the Cirripeds to Crustacea are mentioned in an 

 early page of this Eeport. This therefore is the proper place for the 

 description of the species of the Expedition. The author has, how- 

 ever, paid the subject little attention beyond the examination and 

 figuring of a few species, represented on Plate 96; they have been in 

 better hands, those of Dr. A. A. Gould, who has treated of this de- 

 partment in his Report on the Mollusca of the Expedition. ^The sub- 

 ject, moreover, is receiving a thorough revision from C. Darwin, Esq. 



Among the figures of the Plate referred to, there are several of 

 Cirripeds in the young state. Figures 5 h, 6, 7, 8, represent different 

 species in their free swimming state, and 6 e, /, show the characters of 

 the thorax and abdomen in this state, the six pairs of swimming legs, 

 and the two-jointed abdomen, with a pair of short caudal stylets, end- 

 ing in plumose setaa. In 6 c and 7 b, the position of the two eyes is 

 seen, either side of the anterior part of the body. 6 d shows the form 

 and character of the arms, which correspond to the second pair of 

 antennaB in the Cypris and other Entomostraca. There are five joints 

 and a disk for attachment on the side of the third of these joints. 



After a change of skin, these arms are seen to be combined in a 

 single organ for attachment, as in fig. 69, with each of the component 

 arms still in part distinct, the two terminating in a broad disk, which 

 is two-lobed, being in form like two united disks. 3 a, exhibits the 

 animal thus attached to a supporting surface. After another change 

 of skin, the two valves of the young animal were observed at the base 

 of the pedicel, and the Cirriped had taken on its mature form. 



349 



Vlo. 

 See. p- 



I53&. 



