1(30 Royal Society : — 



are pushed iu like the tubes of a telescope, and covered by a 

 thin cuticle, which may be the blastodermic one. The same 

 envelops also the lateral horns, but has not been seen at the 

 end of the appendages. The carapax is as yet quite smooth, 

 with the lateral horns hanging down. 



6. After the first moult the tail and its spines, which have been 

 pushed out, have a considerable length, and the lateral horns are 

 erected. Only a single pair of small spines is to be seen on the 

 carapax. The glands inside are unicellular. 



7. The Nauplius after the second moult has, besides the dorsal 

 spine, a series of processes all round the edges of the carapax, 

 to which the unicellular glands send their ducts. Besides the 

 oesophagus, two glands, which formerly were indicated by an 

 agglomeration of cells, become visible. These glands are very 

 likely those which, in the Ci/j^ris stage, 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 " ArcJiizoea 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 cara- 

 pax are in connexion with nerves, and present a large network. 

 No nerve-terminations on the lateral horns or 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-sheW is forming underneath it. The first pair of appen- 

 dages 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 Archi- 

 zoea gigas, in which Dohrn, however, has taken the third pair of 

 appendages for the secojid, and the second for the third. 



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

 Archizoea gigas) is figured in the stage just before the meta- 

 morphosis into the Cypris-stage takes place ; the two large com- 

 pound eyes are already developed. 



ILL. The Cypris or pupa stage. 



1 . The Cypris of the Atlantic ( C. fascicularis) has been already 

 described by Claus, who has established the homology of its 

 parts with the Copepods. 



2. Darwin has described the very large Cyjjris of Lepas aus- 

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

 the present species — a further proof of the probability of the sug- 

 gestion that Dohrn's large Nauj>lii are the larva^ of that species. 



