BRACHIOPODA. 
57 
In the brachial valve the cardinal process is quite prominently developed 
and is distinctly bilobed. The socket walls are elevated and recurved; ante¬ 
riorly they are produced into short crural bases which are not free, but rest 
upon the bottom of the valve. The muscular area is narrow and elongate, and 
consists of a pair of central adductor scars embraced posteriorly by a broader 
pair. From the anterior margin of this area arise two vascular trunks which 
diverge outwardly and recurve, following the margins of the valve. These give 
off a series of branches externally and probably a shorter series toward the 
center of the valve. The ovarian markings are very distinct about the bases 
of the dental sockets. 
The external surface of the shell is smooth or covered with very fine con¬ 
centric lines. The shell substance is fibrous and apparently impunctate. 
Whether this species was spiriferous has not been determined, none of the 
specimens examined having shown evidence of brachial supports. In some 
respects the characters of the species are suggestive of Orthis ; for example, 
the well developed, bilobed, recurved cardinal process, filling the delthyrium 
of the brachial valve and extending beyond the plane of the cardinal area; 
the vascular sinuses, and to some extent, the arrangement of the muscular 
impressions. These features, taken in connection with the delthyrium of the 
pedicle-valve, which does not appear to have been covered, though sometimes 
partially filled with an apical accretion, may perhaps be interpreted as confirm¬ 
atory evidence of the non-spiriferous character of the species. 
Metaplasia pyxidata wfis described from the Oriskany fauna of Cumberland, 
Maryland. It is known to occur also in the Oriskany of New York and Canada, 
as well as in the decomposed chert of the Corniferous limestone in the Province 
of Ontario. 
It may be here observed that the very peculiar species Spirifer cheiroptijx, 
described by d’Archiac and de VERNEUiL,*from the middle Devonian at Paflfrath, 
and its ally in the Carboniferous limestones of Vise, S. Oceani, d’Orbigny,f have 
*0n the Fossils of the Older Deposits of the Rhenish Pi-ovinces: Trans. Geol. Soc. London, vol. vi, 
p. 370, pi. XXXV, figs. 6, a, b, 1842. 
t Prodrome de PaMontologie stratigraphique, pi. i, p. 149, 1850. See, also, De Koninck, Faune du Cal- 
caire carbonifere de la Belgique, fie partie; Brachiopodes, p. 132, pi. xxviii, figs. 11-lfi, 1887. 
