REPORT OX THE CIRRIPEDIA. 
29 
large series of sections of the peduncle of Lepcis anatiferci, the presence of the principal 
cement-ducts can everywhere he ascertained ; in the most superior part of the peduncle 
they run at a somewhat greater distance from the innermost layer of longitudinal muscle- 
fibres than is the case in the more inferior sections of the peduncle. The ampullae which 
would represent the commencements of the cement-ducts I have not observed. The two 
ducts run in a zig-zag line, whence in many sections parts of them 0'3 mm. in length are 
represented. I have not been able to follow the cement-ducts quite up to the inferior 
extremity of the peduncle. The wall of the duct itself is irregularly folded in all my 
preparations of Lepas anatifera ; towards the interior of the canal it seems to be invested 
with a thin cuticle, for, when a transverse section is studied, its interior is always 
limited by a sharp smooth line ; for the rest, I have not a very clear notion of 
the cellular structure of the canal. The condition of the specimens of Conchoderma 
virgatum at my disposal has only allowed of my making a preparation of the glands. 
They are very small, measuring not quite 0‘06 mm. Their nuclei are nearly circular, 
and have a diameter of about (P024 mm. In one of the glands a little nucleolus was 
visible, though not very distinctly. The thin cuticle which invests the canal that passes 
away from the gland in Conchoderma virgatum was visible also round the glands them- 
selves. I found Krolin’s statement as to the occurrence of the cement-glands for the 
main part in the parenchymatous tissue of the mantle to be quite correct. 
In Scalpellum I studied the cement-apparatus in two species in greater detail, viz., in 
Scalpellum vidgare, Leach, and in Scalpellum regium (Wyv. Thoms.), Hoek. In these 
two species this apparatus is, curiously enough, not quite built up after the same type. 
That of Scalpellum vulgare has been described already by Darwin. 1 In young specimens, 
Darwin says, the attachment is performed by cement proceeding exclusively from the 
antennae of the larva ; in older and full-grown specimens the cement is poured out 
through a straight row of orifices along the rostral edge, thus causing a narrow margin 
to adhere firmly to the thin and cylindrical branches of the coralline. “ At each period 
of growth the corium (the soft flesh, the mass of connective tissue with the muscles of 
the peduncle) recedes a little from the attached portion of the peduncle ; of which portion 
the greater part is thus left empty, &c. . . . The two cement-glands are seated high up on 
the sides of the peduncle ; the two cement-ducts proceeding from them, are bo o ths of 
an inch (0‘039 mm.) in diameter and run in a zig-zag line ; at the point where they pass 
through the corium to enter the lower attached portion of the peduncle they become 
closely approximated, and partially imbedded in the membrane of the peduncle. They run 
together along the rostral edge, giving out through each orifice a little disk of brownish 
cement, and finally they enter the larval antennae.” 
The specimen of Scalpellum vidgare, whose cement-apparatus I have investi- 
gated, had a peduncle of about 9 mm. in length, and was attached by its under surface 
1 Darwin, Lepadicke, 1851, p. 226. 
