146 Mr. H. J. Carter on Holasterella and Hemiasterella. 
These sheets are more or less traversed perpendicularly by a 
columnar structure of the limestone itself, which is often white 
and looks very much like the fluted fossil cord-spicules of 
Hyalonema Smithii (fig. 13 &c. pi. ix. 1 Annals,’ l. c.) —an 
opinion that seems at first to be strengthened by the other 
minute organisms of the rock (among which there are frag¬ 
ments of sponge-spicules) being all composed of the same kind 
of white calcite , contrasting strongly with the black colour 
of the limestone in which they are imbedded. But here also 
no sponge-spicule can be recognized by its definite form, and 
the white columnar calcite appears in veins rather than in 
ends of columns on the horizontal section. Thus with much 
appearance here, again, of organic origin, there is nothing to 
substantiate it satisfactorily. 
Hemiasterella, n. gen. 
Having described and illustrated the interesting fossil 
sponge from the Upper Carboniferous Limestone lately sent 
to me by Mr. James Thomson, I naturally recur to my know¬ 
ledge of the recent sponges to see if there are any kinds known 
which might be linked with this species; but, as already 
stated, 1 can find none exactly, although there are sponges 
which are partly composed of stellates and partly of linear 
spicules alone , which is the next grade perhaps to that of 
being composed of the former only. 
Of these sponges we know Xenospongia patelliformis , as 
before stated, to be one; and two others have been found in the 
late Dr. Bowerbank’s collection, now in the British Museum, 
which, as they are new and nearly allied in spiculation to 
Holasterella conferta , will at once be described under the 
generic appellation of “ Hemiasterella ,” i. e. half composed 
of stellates which, for the most part, as before stated, are 
bodiless or without inflation at the point of junction at the 
rays. 
Hemiasterella typus , n. sp. (PI. XXI. fig. 9, a, b.) 
General form bowl-shaped, elliptical, with thin flexible wall 
and deep-toothed irregular edges, proliferous on the inner 
side. Colour white. Substance cork-like. Surface shallow- 
rugose-reticulate on each side, covered with a white incrus¬ 
tation of little stellates through which long setaceous acuates 
project. Pores and vents not conspicuous, the latter probably 
numerous and small, being the outlets of so many small excre¬ 
tory systems, as is generally the case with this kind of sponges. 
Internal structure tough, areolar, composed of light flaky 
