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POLYZOA.] UPPER PALEOZOIC RADIATA. 113 4th Class. POLYZOA. See p. 44. Genus. FENESTELLA. See page 49. Fenestella carinata (.M c Coy)■ Ref.—M c Coy, Syn. Garb. Foss. Irel. t. 28. f. 2. Sp. Ch.—Interstices externally close together, irregularly bifurcate; dissepiments and interstices flattened, of equal breadth, and on the same level; fenestrules circular; poriferous face of interstices angular, with a strong, longitudinal keel in the middle; dissepiments very thin, small, rounded; fenestrules elongate, oval, two in one line measured longitudinally or transversely. Two irregular rows of pores with projecting margins, and one irregular row of small ones on the central keel. This coral, to the naked eye, has the appearance of a perfectly flat surface, with regular, round dots, resembling pin-holes. Position and Locality.—Carboniferous limestone, Derbyshire, and Isle of Man. The original Irish localities were the lower limestone of College Hall, Tynan (abundant), and in the calp of Malahide, Dublin. Fenestella Formosa (M c Coy). Ref.—M c Coy, Syn. Carb. Foss. Irel. t. 29. f. 2. Sp. Ch.—Corallum forming flat leaf-like expansions, about one inch long and half inch wide; interstices thin, irregularly branching, about three in the space of one line; fenestrules large, irregular in size and shape; dissepiments very thin; pores of the sides of the interstices large, numerous, their thickened edges indenting the margin, four or five to the length of a fenestrule; at each bifurcation, and at each setting off of a dissepiment is one pore, nearly twice the size of the others; in the middle of each dissepiment is placed one oval pore, and on the strong keel of the interstices is a very regular row of small pores, all having raised margins. To the naked eye it has much of the habit of the common Fenestella undulata (Phill), but the disposition of the pores separates them at once; it is very constant in its characters, several specimens from different localities presenting precisely the same structure. Position and Locality.—Rare in the carboniferous limestone of Derbyshire. The original Irish localities were in the carboniferous slate of Hook Head, Wexford (common) ; in the carboniferous slate at Currens, Tralee; in the black upper limestone of Killymeal, Dungannon (the figured specimen). Fenestella membranacea {Phill. Sp.) Syn. and Ref.—Retepora membranacea Phill. Geol. York. Vol. II. t. 1. f. 1 to 6. Sp. Ch.—Elongate conical; interstices straight, equidistant, with a sharp, central keel; dissepiments nearly equal in thickness to the interstices; fenestrules five in the space of one line, measured transversely, four in one line measured longitudinally, elongate, rather wider than the interstices, nearly three times as long as wide; pores small, about three to the length of a fenestrule; non-poriferous face granulated. This species is remarkable for its elongate conical shape, and very regular elongate oblong fenestrules. I noticed (Syn. Carb. Foss. Ireland, p. 202) that it was “fixed at the base by long, solid, non-poriferous roots of considerable thickness,” these root-shaped processes much resemble Serpube when found detached, they arise irregularly from various points near the small end, and are usually under a line in diameter, and from one to two or three inches in length, and irregularly flexuous; they occasionally occur in other species. This species often attains nine or ten inches in length. I have occasionally seen specimens with traces of the external sheath supposed to characterise the genus TIemitrypa. Position and Locality.—Common in the carboniferous limestone of Derbyshire. Q