Potyzoa.] UPPER PALZZOZOIC RADIATA. 115 
extending upwards from the sides and meeting those from the adjoining interstice at an angle directed 
upwards, bearing two alternating rows of cell-pores. 
Differs from Fenestella in the large number of rows of pores on each interstice, and in having pores 
on the dissepiments, and from Polypora it differs in the keels and linear arrangement of the pores on 
the interstices and also in the poriferous character of the dissepiments; the angulated form of these latter 
is not peculiar to the genus but occurs in some otherwise very different cretaceous forms. As I have 
pointed out in Fenestella, long, solid, root-like fibres occasionally extend from various parts near the base 
of the polypidom. 
SYNOCLADIA VIRGULACEA (Phill. Sp.) 
Syn. and Ref—Retepora, id. Phil. Trans. Geol. Soc. 2nd Series, Vol. IIT. t. 12. f. 6. 
Synocladia id. King. Perm. Fos. t. 4. f. 1 to 8. 
Sp. Ch.—Corallum irregularly funnel-shaped, much wider than high; interstices slightly unequal, aver- 
aging one third of a line wide, branching at short intervals and occasionally anastomosing, rounded and 
smooth exteriorly, bearing on the inner side from three to five rows of cell-pores their own diameter 
apart, separated by longitudinal keels bearing small vesicles alternating with the cell-pores; dissepiments 
usually oblique, often disconnected or angulated upwards in the middle, thin, and bearing on the inner 
side two rows of approximate alternating cell-pores, resembling those of the interstices; fenestrules sub- 
equal, irregularly quadrate, varying from three to four in the space of two lines measured transversely, or 
longitudinally. 
Position and Locality.—Very abundant, forming cup-shaped masses three or four inches in diameter in 
the magnesian limestone of Humbleton Hill. 
Genus. POLYPORA (A°Coy). 
Ref—M°Coy, Synopsis Carb, Foss. Irel. p. 206. 
Gen. Char.—Corallum forming a delicate, reticulated, calcareous expansion, usually fan-shaped; inter- 
stices round, having on one side from three to five rows of cell-openings, the margins usually not projecting ; 
interstices connected by thin, transverse, non-poriferous dissepiments ; reverse rounded, striated or granulated. 
I have not seen any infundibuliform species of this genus, which is easily distinguished from Lenestella 
by the numerous rows of pores on the uncarinated interstices, and from Letepora by the nonporiferous 
dissepiments. The genus is very common in the carboniferous series. 
PoLYPORA DENDROIDES (J/*Coy). 
Ref —MCoy, Syn. Carb. Foss. Irel. t. 29. f. 9. 
Sp. Ch.—Corallum flat, fan-shaped, usually about one inch long and one and a half inch wide; inter- 
stices divaricating, branching at short irregular intervals, about half a line wide; obverse with five rows 
of small, close, impressed quincuncially arranged pores; reverse longitudinally striated; dissepiments very 
thin, often oblique, giving a rhomboidal outline to the fenestrules which are about two-thirds of a line 
wide and usually a little more or less than a line long. 
This species has a peculiar aspect from the arched divarications or divergence of the interstices. 
Position and Locality—Not uncommon in the carboniferous limestone of Derbyshire. The original 
Irish localities were the arenaceous limestone of Townparks, Killeshandra; lower limestone of Kildare; and 
upper limestone of Black Lion, Enniskillen. 
Q2 
