12 BRITISH PALAZOZOIC FOSSILS. [Zoopuyra, 
diaphragms in the small tubes slightly more or less than their diameter apart, two inter-diaphragmal 
spaces in the large tubes slightly exceeding the diameter. 
So exactly does this resemble the Palwopora interstincta (Wahl. Sp.) (Porites pyriformis of Lonsdale, 
Silur. Syst.), that I have little doubt it has often been confounded with it, although an attentive exami- 
nation will shew that the distinctly walled tubes are smooth within and perfectly destitute of lamellx. 
I have seen this coral also in large masses in the Upper Silurian limestone of Gothland. It may be 
distinguished from the very nearly allied Manon (Fistulipora) cribrosa (Gold. Sp.) by the smaller size of 
the cell-tubes and their greater number in a given space, their proportionate distance being pretty nearly 
the same. In both the British and foreign specimens the cells are so beautifully distinct that it would 
be impossible to overlook the notches or rudimentary lamellee if they existed. 
Position and Locality—Forming large masses, not uncommonly in the Wenlock limestone, near 
Aymestry, Herefordshire. 
Explanation of Figures.—Plate 1. C. fig. 1. Portion of large mass natural size, from near Aymestry, 
exhibiting the surface above, and rough weathered section below, shewing the main tubes distinct from 
the capillary ccenenchyme.—Fig. | a, Horizontal section magnified six diameters, shewing the thick-walled 
non-lamelliferous circular main tubes, and the small polygonal intervening ones.—Fig. 16. Side view of 
weathered portion, shewing the diaphragms in both sorts of vertical tubes. 
Genus. STROMATOPORA (Gold.) 
Ref.—-Gold. Pet. Germ. p. 21. 
Gen. Char.—Corallum calcareous, forming large amorphous masses, composed of very thin, superposed 
layers of minute vesicular tissue, of the thickness of one cell each, occasionally marked on the upper surface 
with extremely obscure distant quincuncially arranged small pits. 
The general impression that the Stromatoporw are sponges, is, I think, manifestly incorrect, inasmuch 
as the vesicular tissue of the whole mass is composed of minute curved calcareous plates, forming an immovable 
corallum incapable of those systolic and diastolic motions, essential to the life of a sponge; on the other 
hand, there is an approximation to the structure between the cell-tubes of Palwopora, Pistulipora, &e.; and 
it seems to me that as the Goniopore differ from the deep-celled Astr@a in haying their polyps exserted, 
and consequently forming little or no cell-cup on the surface of the corallum, so the Stromatopore may be 
placed beside Fistulipora or Paleopora, the cell-tubes being supposed to be absent for the same reason as 
in the Goniopora; and this I think is rendered more likely by the existence of the small regularly-disposed 
obscure pits which I have noticed, and which are distant about as far from each other as the tubes of 
the above genera usually are; so faintly marked are they, however, that it is only by a favourable incidence 
of oblique light and using a lens of low power that they can in general be detected; as the specimens 
decompose by weathering, the depressions often become more marked, extending into the mass like holes, 
and perforating down through many layers, in the manner of the more strongly marked yermicular perforations 
of the Caunopora placenta. As neither Stromatopora, nor the subgenus Caunopora, have any radiating lamell, 
they should be most probably placed among the Zoophytaria in the family Tubiporide near Fistulipora. 
I have noted in the Devonian species of the subgenus Cawnopora, that the tubes increase (in some instances 
at least) by lateral budding; the young, when still imperfectly separated, not indenting the circular wall of 
the parent, and being much smaller; thus agreeing with the Madreporacea rather than with the Tubiporide, 
strengthening the impression which I entertained of the transition between these groups by Palwopora on 
the one hand, and /istulipora on the other. 
STROMATOPORA STRIATELLA (d Orb.) 
Ref. and Syn-—D’Orb. Prod. Pal. p. 51. Stromatopora concentrica (Lonsd. Sil. Syst. t. 15. f. 31., not of Gold.) 
Sp. Ch.—Corallum forming hemispherical or flattened expansions from three to eighteen inches in diameter, 
composed of extremely thin regular concentric layers of small rounded cells; eleven or twelve layers in the 
