235 
Avictjlopecten Poebesi, F. McCoy. 
Fecten Forhesi, F. McCoy, 1844, Synop. Garb. Foss. Ireland, p. 95, pi. 15, fig. 20. 
This shell is small, suhorhicular, and slightly convex. Its surface is 
ornamented with thin, radiating ribs, originating at the beak and extending 
to the margins ; between each pair of these ribs, and at some distance from 
the beak, arises a slightly thinner rib : these ribs are crossed by very thin, 
concentric, nearly equidistant wrinkles, very close together, producing a 
check pattern. The ears are small, the posterior ear terminates in a right 
angle, while the anterior ear is rounded and better defined ; both are longi- 
tudinally striated. 
Dimensions . — The length and breadth are both about twelve milli- 
metres. 
Relations and Differences. — This species somewhat resembles my A. 
nohilis, but differs from it by the great number of its concentric wrinkles. 
Horizon and Localities . — A single badly -preserved specimen was found 
at Burragood, but I have been able to determine it with certainty by com- 
paring it with numerous specimens from the Carboniferous Limestone of 
Little Island, Ireland, for which I am indebted to Mr. Edward Wood, of 
Bichmond, Yorkshire. 
Aviculopecten tessellatus, J. Fhillips. 
PI. XXII, Fig. 11. 
Avicula tessellata , J. Phillips, 1836, Geol. Yorkshire, II, p. 211, pi. 6, fig. G. 
,, ,, L. G. de Kouinck, 1842, Descr. Anim. Foss. Terr. Carb. Belg., p. 
134, pi 6, fig. 2, 4, and 11 (bad). 
3Leleagrina tessellata, F. McCoy, 1844, Synop. Carb. Foss. Ireland, p. 81. 
Avicula tessellata, Idem, 1847, Ann. Mag. Xat. Hist., XX, p. 299. 
This is a small, suborbicular, inequivalved shell, nearly as long as 
broad. The ris^ht valve is a little more ventricose than the left. The surface 
is ornamented with from twelve to fifteen thin, nearly equidistant, nodose 
folds ; the nodes are produced by the concentric lines of growth which are 
2 I 
