170 DEVONIAN FAUNA. 



branches, and apparently less prominent peristomes. Our species thus comes 

 nearly midway between F. Gestriensis and F. funicula. 



Of the Carboniferous species described by Phillips and by M'Coy F. poly- 

 porata, Ph., 1 approaches the present species most nearly, but it seems to be 

 distinguished by having a larger number of cells, and by the total absence of a 

 keel, which makes M'Coy regard it as approaching the confines of the genus 

 Polypora. 



•3. Fenestella artheitica, Phillips. PI. XIX, figs. 5 — 10. 



? 1827. Ketepora antiqua, Goldfuss. Petref. Germanica, p. 28, pi. ix, figs. 10 a, b. 

 1841. Fenestella arthritica, var. y, Phillips. Pal. Foss., p. 25, pi. xii, figs. 



36 a, b (only). 



Description. — Zoarium in flattish expansions. Fenestrules regularly oval and 

 very uniform in size, about eight to the length of 10 mm., and thirteen or fifteen 

 to the breadth of 10 mm. Branches rather narrower than the fenestrules, 

 thickening at the dissepiments (so that when the latter alternate the branches are 

 even and slightly undulating, and when they are level the branches are straight 

 and nodulous), divaricating very slowly, often not once in fifteen fenestrules. 

 Dissepiments broad, bi-concave, as large as the branches. Branches divided by a 

 strong, straight, central wall, which is continued upward to a height equal to that 

 of the cells in a thin, free keel or knife-edge, on each side of which is a row of 

 parallel or alternate cells at the rate of four to a fenestrule, with large, circular, 

 elevated mouths. Cells large, suboval in horizontal section, oblong in perpen- 

 dicular longitudinal section, and oval in perpendicular transverse section, the 

 height of the cells being greater than their width. Cell-mouths large, circular, 

 elevated. Non-poriferous face of branches very convex transversely, covered with 

 several irregular rows of tubercles or nodes, and in section showing a thick coat 

 of dense tissue permeated by some very minute, irregular, longitudinal veins or 

 canals, and of a thickness equal to the height of the cells. Poriferous face having 

 a similar but thinner coat, which differs from the other by being without venation 

 and in having numerous, small, tubular processes permeating it almost per- 

 pendicularly and rising above its surface. 



Size of Fragment. — 23 mm. by 18 mm. 



fjiirnlllif. — Lummaton. Four or five specimens are in my Collection, besides 



some which have been used for sections. 



1 1836, Phillips, ' Geol. York,' vol. ii, p. 199, pi. i, figs. 19, 20 ; and 1844, M'Coy, ' Syn. Carb. 

 Foss. Ireland,' p. 203. 



