could be defined in it. Unfortunately we possess only this single
complete series of observations, and its results cannot be regarded at
once as universally applicable; thus the young Hermit Crabs retain the
general aspect and mode of locomotion of Zoeae, whilst the rudiments of
the thoracic and abdominal feet are growing, and then, when these come
into action, appear at once in a perfectly new form, which differs from
that of the adult animal chiefly by the complete symmetry of the body
and by the presence of four pairs of well-developed natatory feet on the
abdomen.* (* Glaucothoe Peronii, M.-Edw., may be a young and still
symmetrical Pagurus of this kind.)

(FIGURE 27. Zoea of a Palaemon residing upon Rhizostoma cruciatum,
Less., magnified 45 diam.)

The development of the Palinuridiae seems to be very peculiar. Claus
found in the ova of the Spiny Lobster (Palinurus), embryos with a
completely segmented body, but wanting the appendages of the tail,
abdomen, and last two segments of the middle-body; they possess a single
median and considerably compound eye; the anterior antennae are simple,
the posterior furnished with a small secondary branch; the mandibles
have no palpi; the maxillipedes of the third pair, like the two
following pairs of feet, are divided into two branches of nearly equal
length; whilst the last of the existing pairs of feet and the second
pair of maxillipedes bear only an inconsiderable secondary branch.
Coste, as is well known, asserts that he has bred young Phyllosomata
from the ova of this lobster--a statement that requires further proof,
especially as the more recent investigations of Claus upon Phyllosoma by
no means appear to be in its favour.

The large compound eyes, which usually soon become moveable, and