Cerapus and Dercothoe, Lestrigonus and Hyperia) or even families
(Hyperines anormales and Hyperines ordinaires). Nevertheless it is only
developed when the animals are nearly full-grown. Up to this period the
young resemble the females in a general way, even in some cases in which
these differ more widely than the males from the "Type" of the order.
Thus in the male Shore-hoppers (Orchestia) the second pair of the
anterior feet is provided with a powerful hand, as in the majority of
the Amphipoda, but very differently constructed in the females. The
young, nevertheless, resemble the female. Thus also,--and this is an
extremely rare case,* (* "I know of no case in which the inferior
(antennae) are obsolete, when the superior are developed," Dana.
(Darwin, 'Monograph on the Subclass Cirripedia, Lepadidae' page
15.)--the females of Brachyscelus are destitute of the posterior (or
inferior) antennae; the male possesses them like other Amphipodae; in
the young I, like Spence Bate, can find no trace of them.

It is, however, to be particularly remarked, that the development of the
sexual peculiarities does not stand still on the attainment of sexual
maturity.

(FIGURE 50. Foot of the second pair ("second pair of gnathopoda") of the
male of Orchestia Tucurauna, magnified 15 diam.

FIGURE 51. Foot of the second pair ("second pair of gnathopoda") of the
female of Orchestia Tucurauna, magnified 15 diam.)

For example, the younger sexually mature males of Orchestia Tucurauna,
n. sp., have slender inferior antennae, with the joints of the flagellum
not fused together, the clasping margin ("palm," Sp. Bate) of the hand
in the second pair of feet is uniformly convex, the last pair of feet is