(Fig. 56. Nauplius of Sacculina purpurea, shortly before the second moult, magnified 180 diam. We may recognise in the first pair of feet the future adherent feet, and in the abdomen six pairs of natatory feet with long setæ. Fig. 57. Pupa of a Balanide (Chthamalus ?), magnified. The adherent feet are retracted within the rather opaque anterior part of the shell. Fig. 58. Pupa of Sacculina purpurea, magnified. The filaments on the adherent feet may be the commencements of the future roots. Fig. 56. Nauplius of _Sacculina purpurea,_ shortly before the second moult, magnified. We may recognise in the first pair of feet the future adherent feet, and in the abdomen six pairs of natatory feet with long setæ. Fig. 57. Pupa of a Balanide (_Chthamalus ?_), magnified. The adherent feet are retracted within the rather opaque anterior part of the shell. Fig. 58. Pupa of _Sacculina purpurea,_ magnified. The filaments on the adherent feet may be the commencements of the future roots. At the base of the inferior antennæ in the Decapoda the so-called “green-gland” has its opening; in the Macrura at the end of a conical process. A similar conical process with an efferent duct traversing it is very striking in most of the Amphipoda. In the Ostracoda, Zenker describes a gland situated in the base of the inferior antennæ, and opening at the extremity of an extraordinarily long “spine.” In the Nauplii of _Cyclops_ and _Cyclopsine,_ Claus finds pale “shell-glands,” which commence in the intermediate pair of limbs (the posterior antennæ). 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 remarkable length, which spring from the angles of the broad frontal margin, and have been interpreted sometimes as antennæ (Burmeister, Darwin) and sometimes as mere “horns of the carapace” (Krohn). The connexion of the “shell-glands” with the frontal horns has been recognised unmistakably in the larvæ of _Lepas,_ and indeed the resemblance of the frontal horns with the conical processes on the inferior antennæ of the Amphipoda, is complete throughout.[5]