1875.] Development of Cirripedia. 131 



terminate in the sucker of the antennae, and are known under the name 

 of cement-glands. Mouth and anus are present. One pair of movable 

 spines on the tail. First " Archizoea stage." 



8. Length of Nauplius in the fourth stage 6 millims. Three or four 

 movable spines on the tail, with the six of the next stage shining through 

 the chitinous coverings. The glands of the carapax are in connexion 

 with nerves, and present a large network. No nerve-terminations on 

 the lateral horns nor on the feelers. All the processes of the carapax, 

 as well as the lateral horns, have openings at the top for letting out the 

 secretions of the glands. 



9. Length of Nauplius in the fifth and last stage 12 millims. Six 

 movable spines on the tail. 



Large masses of fat are assembling in the carapax, and the Cypris- 

 shell is forming underneath it. The first pair of appendages develops 

 inside the antennae of the Cypris, the sucker being formed in the fourth 

 joint, the second of the future antenna. Large compound eyes become 

 visible on both sides of the central eye. 



10. The carapax of the Nauplius has now a diameter of 2 millims. 

 The appendages are very much like those of Archizoea gigas, in which 

 Dohrn, however, has taken the third pair of appendages for the second, 

 and the second for the third. 



11. A specimen of the supposed larva of Lepas australis (Dohrn's 

 Archizoea gigas) is figured in the stage just before the metamorphosis 

 into the Cypris stage takes place ; the two large compound eyes have 

 already developed. 



III. The Cypris or pupa stage. 



1. The Cypris of the Atlantic, C. fascicular -is , has been already described 

 by Claus, who has established the homology of its parts with the 

 Copepods. 



2. Darwin has described the very large Cypris of Lepas australis 

 (length 3 millims.), which is in every way similar to that of the present 

 species — a further proof of the probability of the suggestion that Dohrn's 

 large Nauplii are the larvae of that species. 



3. Our Cypris has a length of 1*3 millim. 



4. A description is given of the antennae with the suckers and their 

 glands, the development of which from the glands in the labrum has been 

 mentioned already. The parts of the mouth (small labrum and three 

 pairs of maxillae and maxillipeds) and the natatory feet, as well as the 

 caudal appendages with the anus at their base, are figured and described. 

 The organs of sense, the digestive organs, and the shell-gland, which is 

 now very conspicuous, offer scarcely any thing that has not been seen 

 already by Darwin and Claus in the Cyprides of the different species of 

 Lepas. 



