APPENDIX. 177 
Moprota Macapamit, Ainahan, 1878. Manual of the Geology of Ireland, pl. in, 
fig. 4. 
— SUBPARALLELA, ft. Etheridge, 1888. Fossils British Paleozoic, p. 285. 
Specific Characters.—Shell moderately convex, especially in front, transversely 
oblong. Superior and inferior borders subparallel. The anterior end is short, 
convexly swollen, and has an almost semicircular margin, passing gradually 
below into the inferior border, which is straight, or with an almost obsolete 
sinuation a little anterior to its centre. The posterior border is truncate, almost 
straight above, rounded below. The hinge-line is straight and long. The 
umbones are tumid, obtuse, elevated above the hinge-line, and continuous, slightly 
excavated in front by a well-marked but small lunule; and are situated very 
anteriorly in the anterior one-sixth of the shell. The valves are convexly 
swollen; there is a shallow contraction which passes obliquely downward and 
backward from the back to the lower margin, becoming wider as it nears the 
lower edge of the valve, which indistinctly marks off the anterior from the 
posterior part of the shell. Posterior to this suleus the shell is diagonally swollen 
from the umbo to the posterior inferior angle, the swelling becoming less marked as 
it proceeds backwards. Above the swelling the valves are flattened and 
compressed into the hinge-line and posterior border. 
Interior.—Casts show the usual arrangement of the adductor and accessory 
muscle-scars. 
The hinge is edentulous, and consists of a thickened mass in front, strongly 
connected with the shell, situated immediately below the umbo, which pro- 
jects downwards, and is slightly bevelled at the expense of the upper portion, 
and of a smooth elongated part posteriorly bevelled at the expense of the lower 
margin. 
Exterior.—The surface is ornamented with many very fine, thread-like striz 
and lines of growth parallel to the border of the valves. Shell thin. 
Dimensions.—The type-specimen, Pl. XXI, fig. 2, measures— 
Antero-posteriorly : . 25 mm. 
Dorso-ventrally ; te Lone, 
Elevation of valve : a <4 
39 
Distribution.—In Carboniferous shales at Ballynascreen, and Slieve Gullion, co. 
Derry; Clogher, co. Tyrone, and Ballycastle, co. Antrim. Lower Carboniferous 
shales of co. Cork and co. Tipperary (Baily). 
Observations.—This shell is very distinct from those named Modiola Macadamii 
by Portlock, although he was not altogether of this opinion, for he says, ‘* Though 
this appears so very distinct a form from Modiola Macadamii, I am disposed to 
think that they all merge one into the other.” As a matter of fact two of the 
varieties of M. Macadamii are very distinct indeed, and all are totally different 
