58 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
DALMANELLA CARINATA var. EPSILON, new variety. 
Pie IOV, wes, B, GD 7 GB 
In the collections of Dalmanella from the Chemung in New York 
the two valves are always separate. This variety epsilon is founded 
on pedicle valves having the earher half of the shell flattened with 
sharply pointed small elevated beak, but the margins of the shell are 
gradually or abruptly turned inward, producing a convex general 
form with flat or gently hollowed center of the shell, instead of the 
concave shell of the normal shape of the species. 
These forms with convex pedicle valves are believed to be not 
specifically distinct from, but rather varietal modifications of, D. 
carinata and are adult individuals, the form resulting from an abrupt 
retardation of radial growth along the perimeter of the shell in later 
stages of its growth. , 
In the normal forms there is the same retardation of growth along 
the perimeter, but it begins early, is continuous and results in bend- 
ing the margin outward instead of inward, making a concave pedicle 
valve. 
Types of variety epsilon are represented on Plate TV by — 
Fig.3 (Ith. 3K, lvvv, 2), mold of interior of pedicle valve. 
Fig. 8 (Ith. 83K, lvvv, 1), mold of interior of pedicle valve. ° 
Fig. 5 (Wv. 7B, 1), 15), (Cornell Univ. Mus.), mold of interior 
of pedicle value. 
Fig. 9 (Wy. 7B, 177, 1), (Cornell Univ. Mus.), mold of interior of 
pedicle valve. 
Fig. 7 (Wv. 7B, 1j*, 5), mold of interior of pedicle valve. 
The localities of DP. carinata and variety epsilon are Ith. 3K, 
lvvv, West Danby, high up in the section a mile or so south of West 
Danby, upper part of Cayuta member; Wv. 7B, 1j', section above. 
Swartwood, from the faunule of the third or Swartwood Tropido- 
leptus zone at the top of the Cayuta member of the Chemung form- 
ation. 
Go 
es 
DALMANELLA VIRGINIA, new species. 
JPleieSs IOV, mes, IO; Jol, 12, iB sual IMs, 
The brachial valve of the type-specimen is subcircular in outline; 
dimensions 20.5 mm. long by 24.2 wide; very gibbous (8.3 mm. deep) 
median sulcus deep, bounded on each side by prominent rounded 
ridges rising 2 or 3 mm. above the bottom of the sulcus; cardinal 
process, crura and muscular scars strongly developed; cardinal 
process sharply cut longitudinally into three parts. These charac- 
ters are illustrated by type-specimen No. 1 of 1380 B® (Plate IV, 
