Poryzoa.| DEVONIAN RADIATA. 75 
ones extending towards the centre, nearly straight for about one-third the diameter, then abruptly diminish- 
ing in strength, and gradually convoluted spirally towards the broad, central area; the secondary lamellie 
much finer than the primary, extending about a fifth of the diameter towards the centre; iternal casts 
with thirty-three to thirty-seven broad, flattened, smooth ribs, separated by deep smooth-edged sulci, (repre- 
senting the primary lamellze) ; these sulci in some specimens, divided by connecting filaments of matrix, produced 
by perforations, in the original plate; each rib divided in the middle by a very fine slit, not reaching quite to 
the narrow base, (representing the secondary lamellze,) becoming nearly as strong as the primary towards 
the broad edge of the cup; no transverse vesicular laminz. Length of imperfect casts, about two and 
half inches; width of same specimen pressed flat, nearly four and half inches; width of ribs between the 
primary sulci at edge of cup, varying from two to three lines. 
The difference in the rate of increase between the cast and exterior, as well as the obtuse apex of the 
former, is produced, as I have shewn in some of the Silurian species, by the solidifying of the narrow 
basal portion of the cavity of the corallum, by a deposition of the sclerenchyme. Several of the specimens 
shew, as I have remarked also in some of the well-preserved Silurian specimens of this genus, that there 
is a total absence of connecting vesicular plates between the lamelle. This large and strongly-marked 
species, from the number of its lamellae, can only be confounded with the P. pluriradialis (Phill. sp.) and 
P. elongata (Phill. sp.) from both of which it differs in its form and great size, width of the ribs on the 
east, absence of puncta, We. 
Position and Locality—Very common in the fine grey Devonian slates of New Quay. 
Explanation of Figures——c. Compressed cast, natural size. d. Worn section of apex, natural size, shewing 
the solid filling up of the young cavity and cause of the obtuse apex of the cast. ¢. Natural section of ditto, 
natural size. 
4th Class. POLYZOA. See p. 44. 
Genus. FENESTELLA. See p. 49. 
FENESTELLA ANTIQUA (Gold. Sp.) 
Syn. and Ref—Retepora antiqua Gold. Pet. Germ. t. 36. f. 3. (not Fenestella antiqua Lonsd. Sil. Syst.) 
Sp. Ch.—Corallum forming irregular funnel-shaped expansions, about one and half inch high ; interstices 
thick, very slightly flexuous, very obtusely carinate, usually two-thirds the width of the fenestrules, some- 
times equalling them ; dissepiments thick, short, at regular intervals ; fenestrules oblong, or slightly oval, 
usually a third longer than wide, sometimes nearly twice as long as wide; pores small, with slightly pro- 
minent margins, nearly their diameter apart, usually three to the length of a fenestrule, and one rather 
larger at the origin of each dissepiment ; three fenestrules in the space of two lines measured longitudinally, 
five in the same space measured transversely. 
The inosculation of the rows of cells, noticed as a specific character by Mr Lonsdale and Prof. Phillips, 
is common to all Fenestelle when in such a state of decomposition (usually in shales) that the internal 
casts of the cells are seen as packed in the interior of the branch. 
The species as above defined, from the Plymouth limestone, agrees exactly with the Eifel coral of 
Goldfuss, but is quite distinct from that in the shales of S. Petherwin, &c., with which Mr Lonsdale 
and Prof. Phillips have confounded it ; the latter coral has been described by me from the carboniferous lime- 
stone of Ireland (see /’. plebeia), and is easily distinguished by its thinner interstices, more distant dis- 
sepiments, and larger and proportionally longer fenestrules, &c. 
Position and Locality—Common in the Devonian limestone of Plymouth. 
