PROaKESS OF MICROSCOPICAL SCIENCE. 139 



All the processes of tlie carapax, as well as tlic lateral horns, have 

 openings at the top for letting out the secretions of the glands. 

 9. Length of Naujilius 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 C?/pm-shell is forming underneath it. The first 

 pair of ajipendages 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 NaupUus 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. Tlie Cypris or pupa stage. 



1. The Cypris of the Atlantic, C. fascicularis, has been already de- 

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

 the Copepods. 2. Darwin has described the very large Cypris of Lepjas 

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

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

 tion that Dohrn's large NaupJii ai"e the larvas of that species. 3. Our 

 Cypris has a length of 1"3 millim. 4. A description is given of the 

 ■ antennno 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 anything that has not been seen already 

 by Darwin and Claus in the Cyprides of the different species of Lcpas. 



IV. TJie metamorphosis of the Cypris into the young Lepas. 

 1. The pupaa are chiefly caught at the very surface of the sea, 

 where they swarm round the dead Vclclla^., on which they ^settle. They 

 rarely take to a colony of old barnacles. 2. Soon after settling the 

 new cirri are formed underneath the natatory feet, the head grows out, 

 the eyes are absorbed, and under the Cy^ms-sholl the primordial 

 valves of the young Lepas apjjear, which persist during its whole life. 

 The C^pm-sliell, witli the old natatory feet, is then thrown off. 



3. The young Lepas begins to form the complete shell, and fastens 

 itself more and more by the cojiious secretions of its glands, which 

 run through the outdrawn and enlarged head into the fixing antennse. 



4. The cirri of the young Lepas develop a larger number of joints, 

 the shell begins to lose its transparency, the body inside turns over a 

 little, as has been described by Darwin, and the young Lepas is com- 

 plete. 



The Minute Structnre of Lucernaria octoradiata has been very 

 fully made out and published before the French Academy (No- 



