382 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
GLYPTORTHIS sp. 2 
Plate 49, E, figures 22-26 
Shell small for the genus, wider than long ; unequally biconvex ; hinge slightly 
narrower than the width at the middle; sides gently rounded; anterior commis- 
sure rectimarginate; anterolateral extremities narrowly rounded; front margin 
very gently curved; surface multicostellate ; costellae numbering about 27, and 
intercalated in 3 generations after the primaries. 
Pedicle valve unevenly convex in lateral profile, the posterior half gently con- 
vex, the front half somewhat flattened ; anterior profile somewhat narrowly con- 
vex in the median region but with steep lateral slopes; umbo and posterior half 
swollen, the slopes in all directions steep to the margins. Median half flattened. 
Interarea long, strongly apsacline. 
Brachial valve gently convex in lateral profile; anterior profile broadly con- 
vex and with median region sulcate; umbo sulcate; sulcus forming a triangular 
depressed area; sulcus occupying about half the width at the anterior margin; 
sulcus bounded by 2 strong costellae on each side and occupied by 6 costellae, 2 
secondary, 2 tertiary and 2 quaternary in appearance. 
Measurements in mm.—1169492, length 4.9, brachial length 4.6, width 6.4, 
hinge width 5.6, thickness 2.6. 
Figured specimen.—116949a. 
Horizon and locality—Hogskin member of the Lincolnshire formation in 
Tennessee: On Maynardville Pike, 1.7 miles north-northeast of Hall Crossroad, 
Fountain City (T.V.A. 146-SW) Quadrangle; 3 mile east-northeast of Red Hill, 
4 miles west-southwest of Thorn Hill, Avondale (T.V.A. 162-SW) Quadrangle ; 
I mile southwest of Washburn, Dutch Valley (T.V.A. 154-SE) Quadrangle. 
Discussion.—This little species is characterized by a subcarinate pedicle valve 
and a fairly strongly sulcate brachial valve. It has some resemblance to G. uni- 
formis but is smaller and more sulcate. It resembles G. subcarinata in size but 
is differently shaped and not strongly sulcate. 
GLYPTORTHIS sp. 3 
Plate 43, A, figures 1-3; plate 50, D, figures 14-18 
Shell small for the genus, wider than long with the hinge narrower than the 
greatest width at the middle; sides and anterior margin gently rounded; anterior 
commissure rectimarginate; surface finely multicostellate ; costellae numbering 
about 66 to 70. 
Pedicle valve with moderately convex lateral profile and broadly but fairly 
strongly convex anterior profile; umbonal and median regions swollen; anterior 
region somewhat flattened; posterolateral slopes short and moderately steep; 
surface marked by a median costella stronger than its fellows; costellae appear 
in about 4 generations. Interarea short, curved, apsacline. 
Brachial valve evenly and moderately convex in lateral profile; anterior pro- 
file gently convex; umbonal region somewhat swollen; umbo sulcate, sulcus 
