122 CARBONIFEROUS CORALS AND BRACHIOPODS 
the typical form of PI. 1, Fig. 3, Dav.^ I feel rather doubt- 
ful whether this is really a local specimen. 
Athyrids. 
Seminula. 
Seminula flcoidea, n. sp., PL II., Figs. 1, la, 16. 
Valves convex, oval, smooth, often exhibiting strong 
concentric growth interruptions. Dorsal valve most con- 
vex under the beak ; beak angle usually nearly a right 
angle, the valve margins being nearly straight on either 
side of the beak ; usually a more or less prominent, broad, 
axial swelling which is, however, never distinctly marked 
off from the flanks ; frontal margin usually continuously 
convex, but occasionally truncated. Margins of valves 
almost uniplanar. Ventral valve uniformly convex, with 
usually a shallow, ill-defined, axial groove, which is only 
conspicuous near the frontal margin. Beak prominent with 
a large foramen ; the lower lip of the foramen is recurved 
(spout-like) over the umbo of the dorsal valve. Spiral 
arms conspicuously and characteristically shown in 
weathered specimens and in sections. Shell structure 
apparently purely fibrous, but occasionally punctations 
are suggested. 
Affinities. — So close are some of the commonest forms 
found in the Bristol area to S. ficus, McCoy, and to S. 
virgoides, McCoy (see PI. 3d, Figs. 22 and 23, Palaeozoic 
Fossils), that it would be unnecessary to create a new 
species, were it not that the shell of our species seems to 
differ essentially in structure from that shown in McCoy’s 
figures (22a and 2M, loc. cit.), (I am, however, far from 
convinced that some of our specimens do not exhibit the 
punctated type of structure, and, furthermore, the preser- 
vation of the shell usually leaves much to be desired.) 
1 Dav. is usei throughout as an abbreviation for Davidson’ s 
Monogixiph of the Brachiopoda, Carboniferous Section, Pal. Soc. 
