608 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
PARASTROPHINA sp. 1 
Plate 106, F, figures 27-32 
Shell small, subcircular in outline, brachial valve deeper than the pedicle one; 
fold low, marked by 2 strong subangular costae; sulcus moderately deep, nar- 
row, marked by a single strong costa; flanks of pedicle valve gently swollen and 
with 3 short costae; flanks of brachial valve swollen and with 2 costae. 
Measurements in mm.—117169, length 7.3, brachial length 7.4, width 8.6, 
thickness 5.7. 
Figured specimen.—117169. 
Horizon and locality—Lower Martinsburg formation (part with Brogniar- 
tella=Salona) in Virginia: On Virginia County Highway 617=910, 0.14 mile 
north of Green Mount Church, Broadway (15’) Quadrangle. 
Discussion.—This peculiar specimen seems to be a Parastrophina rather than 
a Camerella because of its fairly circular form and the shortness of its sulcus and 
fold. Naturally, a section of the beak is the only conclusive means of demonstrat- 
ing the true generic characters. Possibly it is an aberrant form of the specimens 
called Parastrophina hemiplicata, but too few members of that species have been 
found in Virginia to permit the making of a series. Wilson (1914, pl. 4, figs. 
4, 5) illustrates two specimens of P. hemiplicata having a single costa in the 
sulcus, but her specimens are much wider than the Virginia ones. 
PARASTROPHINA sp. 2 
Shell of about medium size, comparable to the medium-sized specimens of 
P., hemiplicata. Transversely and broadly elliptical in outline, paucicostate, the 
fold marked by 3 costae and the sulcus occupied by 2 costae. The flanks of the 
brachial valves have 2 costae. The specimen suggests Perimecocoelia semicostata, 
but the abraded beak of the brachial valve shows alate plates in cross section. 
The species is unlike any other Virginia specimens of Parastrophina in the col- 
lection in its anterior plication. 
Measurements in mm.—111323, length 10.1, brachial length 10.6, width 13.1, 
thickness 7.3. 
Described specimen,—111323. 
Horizon and locality —Oranda formation in Virginia: § mile north of Green 
Mount Church, Broadway (15’) Quadrangle. 
Family PORAMBONITIDAE Davidson, 1853 
Syntrophoidea with thick subparallel plates in both valves defining deep um- 
bonal cavities. Exterior usually pitted. 
It is doubtful if the shells assigned to Porambonites from the Table Head series 
and the upper part of the Pogonip formation in Nevada are actually congeneric 
with Porambonites. The known interiors from the Pogonip formation suggest 
relationship to Noetlingia rather than Porambonites in the presence of a well- 
formed spondylium in the pedicle valve, but they do not have the unusually wide 
hinge characteristic of the Russian genus. 
