128 
Relations and Differences . — I know no species wliicli, by its size 
and robust stracture, can be compared to tbe one I liave just described. 
Ralceaster eucliaris, J. Hall, alone among its congeners, in its ventral surface, 
shows some likeness to it, but its rays are more slender, and its radial plates 
more numerous. The dorsal surface in the two species differs completely ; 
in the one are some large, polygonal, contiguous, radial plates ; and in the 
other, rounded plates relatively much smaller, more numerous, and separated 
from each other by countless small intermedial plates, the presence of which 
alone would prevent confusion. 
Rormation and Localities. — While the greater number of Palaeasters 
actually known have been collected from Silurian or Devonian rocks, P. 
Glaidcei was found in Carboniferous rocks by the learned geologist to whom 
I have the honour of dedicating it.^ Unfortunately, the only specimen found 
is not sufficiently well preserved to allow me to describe it in detail. It 
consists of the external impressions of the ventral and dorsal surfaces of the 
same individual ; the margins and the central disc have suffered much during 
fossilization ; the solid parts have completely disappeared. This individual 
was obtained from Hussell’s Shaft, in a rather friable, calcareous, greenish 
sandstone, composed of grains generally rather fine, but in places reaching 
the size of a small pea, giving the rock the appearance of conglomerate. 
Class — BRTOZOA. 
CYCLOSTOMATA. 
Genus — PENNIE/ETEPOHA, A. d'Orbigny. 
Penniretepoea grandis, McCoy, 
PI. V, Pig. 11. 
Glauconome gr midis, McCoy, 1844, Synop. Garb. Poss. Ireland, p. 199, pi. 28, fig. 3. 
Renniretepora grandis, A. d’Orbigny, 1850, Prodr. Pal., I, p. 153. 
The coenecium of this species is formed of one principal branch, the 
diameter of which is about double that of the lateral branches. The insertion of 
these latter on the principal branch is alternate, and they are inserted at a 
^ I am aware that Salter noted the existence of a fine species of Pala^aster in the Lower Carboniferous 
beds of Barnstaple, but I have never been able to see either the description or the figure, and have therefore been 
unable to compare it with the Australian specimen, [Vide Ann, Mag, Nat. Hist., XX (2), p. 326.] 
