OF DENISON UNIVERSITY. 
105 
BRACHIOPODA. 
I. Streptorhyncus tenuis, 
II. Strophomena patenta, 
HalL 
Hall. 
Genus STREPTORHYNCUS, King. 
I. Streptorhyncus tenuis. Hall. 
{Plate VHI, Fig^. 31, 32, 38.) 
Shell quite large, semi-circular ; cardinal line less than the great- 
est width of the shell, cardinal extremities rounded. Ventral valve 
flat, the beak and immediately adjacent portions slightly elevated. In 
the description of the type specimens this valve is said to be slightly 
concave. Our valve can not be said to be anything more than flat. 
Dorsal valve moderately convex, the umbo not prominent; convex- 
ity, with the exception of a little compression near the cardinal ex- 
tremities, regular. 
Surface marked by numerous, rounded, radiating striae, somewhat 
curved near the cardinal extremities; alternating with these are smaller 
thread-like striae. These radiating striae are crossed by fine concentric 
striae, presenting when magnified, a beautiful, rugose appearance. 
Substance of the shell very thin. 
One of the largest ventral valves is 30 mm. long, and 36 mm. 
wide. Our specimens therefore do not attain the size of the Indiana 
specimens. A dorsal valve is 22 mm. long, 30 mm. wide, and meas- 
ures 26 mm. between the cardinal angles ; its convexity is about 
3.2 mm. 
Locality and position. This is quite a common species in one part 
of the Soldiers’ Home Quarry. Clinton Group. 
Genus STROPHOMENA, Rafinesque. 
H. Strophomena patenta. Hall. 
{Plate VIII, Fig. 34, 35, 36, 37.) 
Leptsena patenta, Hall, 1S52, Pal. New York, Vol. II. 
Strophomena patenta, Hall, 1859, 12th Ann. Rep. Cab. Nat. Hist, of New 
York. 
Strophomena euglypha, Roemer, i860, Sil. Fauna, West. Tennessee. 
Strophomena patenta, Hall and Whitfield, 1875, Pal. Ohio, Vol. H. 
Shell of moderately large size. At various stages of growth they 
