BRACHIOPODA. 
143 
ible. Brachial valve more or less convex, with the beak marginal. External 
surface radiately striated. The interior bears a pair of strong posterior 
adductor scars, lying close together in the umbonal region; their outline is 
elongate-ovate, indicating a progressive increase in size, and they frequently 
appear to be divisible into anterior and posterior elements. In front of them, 
at about the center of the valve, are the small and faint anterior adductor im¬ 
pressions. A low median ridge extends from the apex to beyond the center of 
the valve. External surface marked by elevated striae radiating from the 
beak. 
Substance of the shell composed of perlaceous calcareous laminae which 
constitute the most of the shell. The inner layers appear to be corneous. All 
are impunctate (?-). 
Type, Schizocrania filosa, Hall. 
Observations. We have knowledge of but two clearly defined species of this 
remarkable genus, the type, a not uncommon form in the Hudson group 
in Ohio and Kentucky, usually occurring attached to foreign bodies, not infre¬ 
quently to valves of Strophomena alternata; a shell often of considerable size in 
these localities but represented in the Utica slate of New York by a rather 
diminutive form; and a second species, here described under the name S. Schu- 
cherti, from the Utica horizon of the Cincinnati group at Covington, Kentucky. 
It was observed in the original discussion of this genus that these fossils were 
probably parasitic or adherent by the surfaces of their lower valves, as in 
the case of most palaeozoic Cranias. It seems necessary to modify this 
opinion as our present material affords evidence that the lower surface of the 
pedicle-valve retains its concentric markings with no trace of conformation to 
the body to which the animal may be attached. The pedicle itself was, if we 
may judge from the size of the aperture, of very great strength and the pedi¬ 
cle-valve, being of somewhat less diameter than the brachial, was overlapped 
by it, and it is very apparent that this overlapping edge of the upper valve has 
formed an important accessory means of attachment. (See Plate IV g, figs. 25, 
29, 33-35.) 
