The _Echinoderms_ are represented by a few _Crinoids_, and by a
Sea-urchin belonging to the genus _Eocidaris_. The latter genus
is nearly allied to the _Archoeocidaris_ of the Carboniferous, so
that this Permian form belongs to a characteristically Palaeozoic
type.
A few _Annelides_ (_Spirorbis, Vermilia_, &c.) have been described,
but are of no special importance. Amongst the _Crustaceans_,
however, we have to note the total absence of the great Palaeozoic
group of the _Trilobites_; whilst the little _Ostracoda_ and
_Phyllopods_ still continue to be represented. We have also to
note the first appearance here of the "Short-tailed" Decapods or
Crabs (_Brachyura_), the highest of all the groups of _Crustacea_,
in the person of _Hemitrochiscus paradoxus_, an extremely minute
Crab from the Permian of Germany.
[Illustration: Fig. 135.--Brachiopods of the Permian formation.
a, _Producta horrida_; b, _Lingula Credneri_; c, _Terebratula
elongata_; d and e, _Camarophoria globulina_. (After King.)]
Amongst the _Mollusca_, the remains of _Polyzoa_ may fairly be
said to be amongst the most abundant of all the fossils of the
Permian formation, The principal forms of these are the fronds
of the Lace-corals (_Fenestella, Retepora_, and _Synocladia_),
which are very abundant in the Magnesian Limestone of the north
of England, and belong to various highly characteristic species
(such as _Fenestella retiformis, Retepora Ehrenbergi_, and
_Synocladia virgulacea_).
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