88 
A ug. F. Foerste 
margin number about ii in a width of 5 mm. The radiating striae 
on the dorsal valve are still finer. The concentric striae on both 
valves can be seen only with a lens. 
The interior of the pedicel valve shows the crenulations on the 
cardinal margin for a distance of about 4 mm. from the delthyrium. 
The muscular area is triangular fiabelliformj well defined laterally 
but not anteriorly. A median ridge divides the posterior part of 
this area, and near the beak this thickens into a callosity filling the 
median part of the space between the hinge teeth. From this cal- 
losity two short ridges diverge anteriorly, in addition to the median 
ridge. 
The cardinal process of the brachial valve consists of two lobes, 
slightly over 2 mm. long, diverging at angles of 50° from each 
other, in a plane at right angles with the shell. Anterior to the 
cardinal process, the shell is thickened so as to form a subrhom- 
boidal space, anterior to which there are only faint traces of mus- 
cular impressions. The posterior parts of the brachial valve, and 
also of that part of the pedicel valve which lies outside of the mus- 
cular area, are marked by coarse granules, becoming more numerous 
and finer anteriorly. In some shells only the coarser granules are 
present. 
Waldron bed: Newsom, Tennessee. 
Meristina maria-roemeri, var. nov. 
{Plate II, Fig. 2Q A, B.) 
This species is evidently closely related to Meristina maria of 
the Waldron horizon, but is readily distinguished by its sub- 
trigonal outline, especially when viewed from the side of the pedi- 
cel valve. This subtrigonal outline is produced by a straighten- 
ing of the postero-lateral outline. The strongly sinuous outline of 
the anterior margins of the valves is normal in this form while in 
typical forms of Meristina maria it usually is less developed. See 
fig. 12, plate 5, of Roemer’s work in the Silurian Fossils of West- 
ern T ennessee. 
Brownsport bed: north of landing at Glenkirk, at mouth of 
Beech creek; glade southwest of Brownsport Furnace, three miles 
west of Vice landing; mound glade half a mile west of road, two 
and one-half miles north of Vice store; Martin’s Mills; old Colonel 
Jim Smith’s place, nine miles east of Savannah; bridge two miles 
west of Pegram; all in Tennessee. 
i 
A 
