114 ; BRITISH PALASOZOIC FOSSILS. [Pouyzoa. 
FENESTELLA PLEBEIA (M‘Coy). See page 76. 
Position and Locality—Common in the carboniferous limestone of Derbyshire. The original Irish locali- 
ties were the arenaceous limestone of Killybrone, Killala; carboniferous slate of Poulscadden, Howth; and 
Malahide, Dublin; lower limestone of Howth, Dublin, and Little Island, Cork; calp of Malahide; Bun- 
doran, and Ballintrillick ; upper limestone of Killymeal, Dungannon ; carboniferous shales of Ringstown, Mount 
Rath, and Rahan’s Bay. 
FENESTELLA POLYPORATA (Phill. Sp.) 
Ref—Retepora polyporata Phill. Geol. York. Vol. II. t. 1. f. 19, 20. 
Sp. Ch.—Interstices thick, rounded, carinated, irregularly branched; dissepiments short, thin, placed at 
irregular distances ; fenestrules large, very irregular in size and shape, averaging three in two lines, measured 
longitudinally, five in the same space measured transversely; pores very small, impressed, from five to seven 
to the length of a fenestrule. 
Position and Locality—Carboniferous limestone, Derbyshire. 
FENESTELLA RETIFORMIS (Schloth. Sp.) 
Ref. and Syn—Keratophytes retiformis Schlotheim Akad. Munch. Vol. VI. t. 1. f. 1, 2. = Retepora flus- 
tracea (Phill.) Geol. Trans. 2nd Series, Vol. III. t. 12. f. 8. = Gorgonia infundibuliformis and antiqua 
Gold. Pet. Germ. t. 36. f. 2 and 3. King, Perm. Foss. t. 2. f. 8. to 11. 
Sp. Ch.—Corallum forming very irregularly folded, short, wide, funnel-shaped expansions; interstices 
thin, keel strong, with vesicular tubercles less than their diameter apart, and alternating with the cell-pores 
which are very prominent, strongly indenting the margin, varying from two to three to the length of a 
fenestrule ; dissepiments strong, at regular intervals; fenestrules regular, oblong or oval, usually about two- 
thirds the width of the interstices, and nearly twice as long as wide (five or six in two lines, transversely 
or longitudinally measured) ; reverse with a few minute pores and irregular longitudinal striz. 
Position and Locality—Very abundant (usually three or four inches or more in diameter) in the mag- 
nesian limestone of Humbleton Hill. 
FENESTELLA UNDULATA (Phill. Sp.) 
Syn. and Ref—Retepora undulata Phill. Geol. York. Vol. II. t. 1. f. 16, 17, 18. 
Sp. Ch.—Interstices and dissepiments very thin; fenestrules large, irregular; pores very large; rather 
distant, prominent, indenting the margin, about four to the length of a fenestrule; reverse with undulating, 
longitudinal strize. 
This is a loosely branched, but very delicate species, the substance of the coral itself being very 
slender; the fenestrules are four or five times the width of the interstices; the pores are only sub-alternate, 
and so large as to give a nodular aspect to the interstices. It grows to upwards of two inches in length; 
there are about two interstices in the space of one line. 
Position and Locality—Rare in the carboniferous limestone of Derbyshire. 
Genus. SYNOCLADIA (King). 
Ref—King, Ann. Nat. Hist. 2nd Series, Vol. III. 
Gen. Char.—Corallum cup-shaped, with a small central root-like base, reticulated, composed of 
rounded, narrow, often-branched interstices, bearing on the inner face from three to five alternating lon- 
gitudinal rows of prominent-edged pores, separated by narrow keels, studded with small, irregular vesicles 
alternating with the cell-pores; dissepiments thin, rarely direct, usually forming short spur-shaped pinne 
