92 



HISTORY OF CRUSTACEA. 



CHAP. IX. 



cephala. The Nauplii of the Cirripedia have to undergo 

 several moults whilst in that form ; the Nauplii of the 

 Khizocephala, being astomatous, cannot of course live 

 long as Nauplii, and in the course of only a few days 

 they become transformed into equally astomatous 

 " pupae," as Darwin calls them. 



The carapace folds itself together, so that the little 

 animal acquires the aspect of a bivalve shell, the fore- 

 most limbs become transformed into very peculiar 

 adherent feet (" prehensile antennae," Darwin), and the 

 two following pairs are cast off, like the frontal horns. 

 On the abdomen six pairs of powerful biramose nata- 

 tory feet with long setae have been formed beneath the 



Nauplius-skin, and 

 behind these are 

 two short, setige- 

 rous caudal appen- 

 Fig.57. dages (fig. 58). 



The pupae of the 

 Cirripedia (fig. 57), 



which are likewise 

 astomatous, agree 



completely in all 

 these parts with 

 those of the Khizo- 

 cephala, even to the minutest details of the segmenta- 



9 Fig. 57. Pupa of a Balanide (Chthamalust), magn. 50 diam. The 

 adherent feet are retracted within the rather opaque anterior part of 

 the shell. 



10 Fig. 58. Pupa of Sacculina purpurea, magn. 180 diam. The fila- 

 ments on the adherent feet may be the commencements of the future 

 roots. 



Fig. 58. 10 



