CARBONIFEROUS FOSSILS OF IRELAND. 201 



This coral to tlio naked eye lias the appearance of a perfectly flat surface, with regular, round dots re- 

 sembling pin holes. 



■ Fenestella crassa. {M'Coy. (PL XXIX. fig. 1). 



Sp. Ch. — Spreading; interstices thick, strongly keeled, irregularly branched; dissepiments very thin, di.s- 

 tant; fencstrules large, very elongate, irregular; pores ratlier small, few, twice their diameter apart, without 

 raised margins ; a few irregular, small pores on the central keel ; reverse striated. 



This species is allied to the Fenestella laxa, Phil., but is rather more regular in its habit; it likewise differs 

 in the dissepiments being much thinner, the interstices being strongly carinated, and the greater distance of the 

 pores, which, so far from being tubular, have not even the raised margin found in nearly all of tlie genus. The 

 reverse of the F. laxa is also granulated with great regularity, wliile in the present species it is regularly striated. 

 The figure is taken from a portion of a specimen three inches long, and four and a half inches wide; the inter- 

 stices are hatf a line thick. 



• Fenestella ejuncida. M'Coy. (PI. XXVIII. fig. II). 



Sp. Ch. — Flabelliform, interstices nearly straight, equidistant, very tJiin; dissepiments nearly as thick as 

 the interstices, placed at regular distances ; fenestrules large, nearly equal in size and shape ; oblong, slightly 

 longer than -wide, about three times as wide as the interstices ; pores small, prominent, placed alternately, one 

 at the origin of each dissepiment, and four in the intervening space ; seven or eight interstices in the space 

 of three lines. 



Fenestella flabellata. Pldl. sp. 



Eetepora flabellata. Phil. Geol. York. 



Stp. Ch. — Slightly spreading, irregularly branched; interstices very thin, distinctly carinated ; dissepiments 

 scarcely half as thick as the interstices, equidistant ; fenestrules equal, rectangular, twice as long as wide ; width 

 equal to that of an interstice ; pores very prominent, deeply indenting the margin ; three to the length of a 

 fenestrule ; reverse sharply striated longitudinally. 



A pretty little species, easily distinguished from the F. tenitifila, by its smaller size, and the deep indenta- 

 tions produced by the pores on the margin of the fenestrules, the striae of the obverse are also sharper and 

 more direct. 



Fenestella Formosa. M'Coy. (PI. XXIX. fig. 2). 



Sp. Ch. — Flat, leaf-like ; interstices thin, irregularly branching ; 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 ofi' 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. 



Once seen with the lens this remarkable coral can never be forgotten ; to the naked eye it has much of 

 the habit of tlie common Fenestella undulata, Phil., but the extraordinary disposition of the pores separates 

 them at once ; it is very constant In its characters, several specimens from different localities presenting pre- 

 cisely the same structure ; it forms the most beautiful object for the microscope that can be conceived. Length 

 about one inch, width half an inch ; there are about three interstices in one line. 



Fenestella frutes. M'Coy. (PL XXVIII. fig. 10). 



Sp. Ch. — Flabelliform; rising from a distinct root or trunk, and suddenly expanding to a nearly circular 

 network ; fenestndes broad, usually quadrangular, but rather irregidar in size and shape ; interstices thick, fre- 

 quently branching, slightly flexuous, irregular ; dissepiments thin, at regular distances ; pores very prominent, 



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