50 BRITISH PALAXOZOIC FOSSILS. [ Potyzoa. 
lines; dissepiments thin, averaging two lines apart; fenestrules oblong, usually five or six times longer 
than wide; pores round, alternating or inosculating, prominent, deeply indenting the edges of the thin 
interstices, about twelve to the length of a fenestrule. 
Position and Locality—Not uncommon in the slates of Blain y Cwm, W. of Nantyre, Glyn Ceiriog ; 
Cefn Coedog; and Llansantfraid, Glyn Ceiriog, Denbighshire. 
FENESTELLA PATULA (M°Coy). Pl. 1. C. fig. 20. 
Ref —M‘Coy, Ann. Nat. Hist. 2nd Series, Vol. VI. p. 288. 
Sp. Ch.—Corallum forming small semicircular expansions, about half an inch in diameter; interstices 
broad, strongly carinate, slightly flexuous, and dichotomising very frequently (usually at rather less than 
every line in height) about seven in the space of two lines; fenestrules about one-third wider than the 
interstices, of very irregular shape, but nearly equal in length; dissepiments strong, about half a line apart ; 
pores large, very prominent (about three or four to the length of an interstice). 
This species is more nearly allied to the Retepora (Fenestella) antiqua of Goldfuss than the Silurian 
species referred to it by Lonsdale (/. subantiqua, D’Orb.) From the latter species it is easily distinguished 
by its thick, widely divaricating, and frequently branched interstices, the irregular shape of the fenestrules, 
and the much fewer and more prominent pores. 
Position and Locality-Not uncommon in the Wenlock limestone of Dudley, Staffordshire. 
Explanation of Figures.—P\. 1. C. fig. 20. Natural size, from Dudley.—Fig. 20. Portion of ditto, 
magnified twelve diameters. 
FENESTELLA RIGIDULA (A/‘Coy). PI. 1. C. fig. 19. 
Ref —M°Coy, Ann. Nat. Hist. 2nd Series, Vol. VI. p. 288. 
Sp. Ch.—Corallum formed of very slender, ridged, ‘straight interstices, branching seldom (at distances 
of about every two lines), several interstices often branching at the same height, at a very acute angle, 
about ten interstices in the space of two lines; mesial keel very strong, with two close rows of small 
alternating pores; fenestrules very regular in size and shape, quadrangular, about one-third longer than 
wide, their width about equalling that of the interstice, usually three large thick-edged pores to the length 
of a fenestrule, and one larger at the end of each dissepiment. 
In size, mode of branching, and rigid straightness of the interstices, this is not unlike the /. swé- 
antiqua, but is distinguished by its closer dissepiments, forming shorter fenestrules and its much fewer 
and larger pores. I suspect, from some specimens I have seen, that it is possible some of the figures 
given by Lonsdale in the Silurian System, as the Fenestella prisca (Gold. Sp.) may he coarse, inaccurate 
representations of this species. If this should even prove so, the name I propose should be retained, 
as it has no affinity with the large Devonian coral of Goldfuss. 
Position and Locality —Not uncommon in the Wenlock limestone of Dudley, Staffordshire. 
Explanation of Figures —P\. 1. C. fig. 19. Natural size from Dudley.—Fig.19@. Portion of ditto, 
magnified thirty diameters. , 
FENESTELLA SUBANTIQUA (d’Orb.) 
Ref. and Syn—d Orb. Prod. p. 44. = Fenestella antiqua Lonsd. Sil. Syst. t. 15. f. 16. (not of Goldfuss). 
Sp. Ch.—Corallum formed of very slender, straight interstices, seven or eight in two lines, seldom ~ 
bifureating ; dissepiments rather thick, very regularly placed at about half a line apart; fenestrules rect- 
angular, oblong, about three times longer than wide, rather more than double the width of the interstices ; 
pores small, with thickened prominent edges their own diameter apart, six or seven to the length of 
a fenestrule. 
Mr Lonsdale has identified this species with Retepora antiqua of Goldfuss, which species does not 
probably occur in Silurian strata, and the figure of the Hifel specimen in the Petrefacta Germaniz, represents 
