New Species of that
Genus. By SPENCE BATE, Esq., F.L.S.

[Read January 21, 1858.]

Of the various genera of Decapod Crustacea none are more interesting, or
more difficult of description, than those which constitute the family
Galatheadae.

The interest attaching to these forms arises from the intermediate
position which they occupy in the natural arrangement of the class,
their structure placing them between the Macrura and Brachyura; in
accordance with which we find that, whilst Professor M.-Edwards classes
them among the Macrura, Professor Bell, in his work on the British
Crustacea, places them (more correctly, as we think) in the intermediate
group of Anomura.

This opinion is fully borne out both in the development of the animals
and in their structure in the adult state.

The early form of the larva bears, anteriorly, a resemblance to the
Brachyural type, whilst the caudal appendages assimilate to those of the
Macrura. The same conditions obtain in the young of Anomura. At the time
of birth, the larva, like that of the Brachyura, has only the two
gnathopoda developed, whilst the termination of the tail is like that
of a fish, as in the Macrura. In the adult, the internal antennae possess
short flagella and complementary appendages, such as exist in the order
Brachyura, whilst the external antennae have the long and slender
flagella proper to the Macrura. The _scale_, however, commonly appended
to the external antennae in the latter order is wanting, a circumstance
which exhibits a relation to the Brachyura.

An examination of the legs shows that the coxae are fused with the
thorax, as in the Brachyura, and not articulated with it as in the
Macrura, whilst, on the other hand, the posterior division and caudal
termination approach the Macrural type more nearly than that of the
Brachyura, the animal thus assuming a character intermediate between the
two orders.

But in the description of the several species of the genus _Galathea_, a
peculiar difficulty appears to arise, originating in the affinity which
they bear to each other. So close, in fact, is the approximation, that
the descriptions of the best writers will scarcely avail for the
distinction of the individual species without the assistance of figures.
This arises from the fact that the general characters, upon which the
descriptions are based, vary, in this genus, only in their comparative
degrees of development.

In the three species recognized i