THE PERMIAN PERIOD: 197 
Taxoid Conifers of the Coal-measures. Besides Walchia, a 
characteristic form of these is the UMmania selaginotdes, which 
occurs in the Magnesian Limestone of Durham, the Middle 
Permian of Westmorland, and the “ Kupfer-schiefer” of Ger- 
many. ‘The group of the Cycads, which we shall subsequently 
find to be so characteristic of the vegetation of the Secondary 
period, is, on the other hand, only doubtfully represented in 
the Permian deposits by the singular genus Veggerathia. 
The Protozoans of the Permian rocks are few in number, and 
for the most part imperfectly known. A few Foraminifera have 
been obtained from the Magnesian Limestone of England, 
and the same formation has yielded some ill-understood 
Sponges. It does not seem, however, altogether impossible 
that some of the singular “‘ concretions” of this formation may 
ultimately prove to have an organic structure, though others 
would appear to be clearly of purely inorganic origin. From 
the Permian of Saxony, Professor Geinitz has described two 
species of Spfongillopsis, which he believes to be most nearly 
allied to the existing fresh-water Sponges (Sfongilla). ‘This 
observation has an interest as bearing upon the mode of de- 
position and origin of the Permian sediments. 
The Celenterates are represented in the Permian by but a 
few Corals. These belong partly to the Zabulate and partly 
to the Rugose division ; but the latter great group, so abun- 
dantly represented in Silurian, Devonian, and Carboniferous ~ 
seas, is now extraordinarily reduced in numbers, the British 
strata of this age yielding only species of the single genus 
Polycelia. So far, therefore, as at present known, all the 
characteristic genera of the Rugose Corals of the Carboniferous 
had become extinct before the deposition of the limestones of 
the Middle Permian. 
The Echinoderms are represented by a few Crinoids, and by a 
Sea-urchin belonging to the genus Zocidaris. ‘The latter genus 
is nearly allied to the Archeocidaris of the Carboniferous, so 
that this Permian form belongs to a characteristically Palaeozoic 
type. ; 
A few Annelides (Spirorbis, Vermilta, &c.) have been de- 
scribed, but are of no special importance. Amongst the 
vustaceans, however, we have to note the total absence of 
the great Paleozoic group of the Z7z/odites ; whilst the little 
Ostracoda and FPhyllopods 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. 
