Chap. IX. CIRRIPEDIA AND RHIZOCEPHALA. 91 



and Ci/cIoj)s{ne, Claus finds pale "shell-glands," which 

 commence in the intermediate pair of limbs (the poste- 

 rior antennae). On the other hand in the Nauplii of the 

 Cirripedia and Rhizocephala the *' shell-glands " open 

 at the ends of conical processes, sometimes of most re- 

 markable length, which spring from the angles of the 

 broad frontal margin, and have been interpreted some- 

 times as antennae (Burmeister, Darwin) and sometimes 

 as mere " horns of the carapace " (Krohn). The con- 

 nexion of the "shell-glands" with the frontal horns 

 has been recognised unmistakably in the larvae of 

 Lepas, and indeed the resemblance of the frontal horns 

 with the conical processes on the inferior antennae of 

 the Amphipoda, is complete throughout.^ 



Notwithstanding their agreement in this important 

 peculiarity, the Nauplii of these two orders present 

 material differences in many other particulars. The 

 abdomen of the young Cirripede is produced beneath 

 the anus into a long tail-like appendage which is fur- 

 cate at the extremity, and over the anus there is 

 a second long, spine-like process ; the abdomen in 

 the Rhizocephala terminates in two short points, — in a 

 " moveable caudal fork, as in the Rotatoria," (0. 

 Schmidt). The young Cirripedes have a mouth, 

 stomach, intestine, and anus, and their two posterior 

 pairs of limbs are beset w^ith multifarious teeth, setae, 

 and hooks, which certainly assist in the inception of 

 nourishment. All this is wanting in the young Rhizo- 



8 In connexion with this it may be mentioned that, in the females of 

 Brachijscelus, in which the posterior antennae are deficient, the conical 

 processes with the canal permeating them are nevertheless retained. 



