BRaAcuIopoDA. 847 
valve. The character of this structure in the brachial valve 
is not variable in this genus. 
Type, Gypidula comis, Owen (sp.). 
Distribution. Devonian. 
Capellinia, Hall. 1893. 
(Plate 47, figs. 10-12.) 
Shells large, elongate-subovate ; the relative size and convexity 
of the valves, normal for Psnramerus, are here reversed, the 
brachial valve being the larger and deeper, with full, strongly 
arcuate and incurved umbo and beak, the apex of which is con- 
cealed within the delthyrium of the opposite valve. The 
pedicle-valve has an acute suberect beak which is not arched pos- 
teriorly, but rises directly from the cardinal margins. Below it 
is a broad delthyrium without evidence of deltidial plates; there 
is no hinge-line, but the margins of the delthyrium make sub- 
acute angles with the lateral margins of the valve. Cardinal 
slopes very broad and abrupt. The surface of the pedicle-valve 
is flattened above, while that of the brachial valve is evenly and 
deeply convex ; it also shows a tendency to trilobation or obscure 
radical plication. The arrangement of the internal septa and 
spondylium is the same as in Pentamerus oblongus, except that 
the supporting septa of the brachial valve are higher and more 
nearly vertical. ; 
Type, Capellinia mira, Hall. 
Distribution. Upper Silurian. 
Stricklandinia, Billings. (1863), 1859. 
(Plate 49, figs. 1-7.) 
Shells usually large, elongate-oval, transversely-oval or circular ; 
in some species with a straight hinge-line, more or less extended. 
Valves nearly equal, varying from depressed convex to strongly 
convex. In the interior of the pedicle-valve is a short median 
septum supporting a small, triangular chamber beneath the beak. 
In the brachial valve are two very short or rudimentary socket 
plates, which in some species bear prolonged crura. Both valves 
with distinct cardinal area, that of the pedicle-valve the larger, 
the dorsal area sometimes incurved over the ventral, and con- 
cealing it wholly or in part. 
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