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1895. ] NEW YORK ACADEMY OF SCIENCES. er 
outer are more arched than the inner, and all radiate toward the 
margin of the valve.* 
The ventral valve is moderately convex and oblately orbicular, 
with a short, blunt umbo; and has two low gradually diverging 
ridges, marking off a narrow triangular median area. There is 
a low, striated hinge area, the front edge of which is slightly 
toothed to fit the small pits on each side of the cardinal process 
of the dorsal valve. The interior of the ventral valve has a 
prominent ridge extending from beneath the area, half way to 
the front of the valve; this ridge arises from the indentation of 
the back of the valve by the pedicle groove; the surface of the 
ridge is seamed transversely by arched ridgelets, which mark 
the changing position of the foramen of the pedicle as the shell 
grew; the ridge does not quite reach the umbo, but is separated 
from it by a small, low boss, having a central depression, or 
umbilicus. In the ventral valve the position of the posterior 
adductors is marked by a pair of triangular scars, beginning un- 
der the outer part of the hinge; each scar shows the points of 
attachment of three muscular bands. The scars of the adjustor 
muscles, and of the lateral (anterior adductor ?) muscles run 
parallel to the each other along the sides of the valve, from 
near the hinge line; and they extend further forward than do 
the scars of the adjustors of the dorsal valve. 
Sculpture. As we have only the interior of this shell, the surface 
markings of the outside are scarcely discernible; towards the 
front of the valve, however, they become visible under the lens, 
and are seen to consist of fine concentric ridges; and very fine 
broken, radiating striz, visible only in a few places. 
Size. Length of the dorsal valve 8 mm., width 10mm. The 
ventral valve is 1 mm. longer than the dorsal. 
Horizon and locality. Found by W. D. Matthew in the upper 
part of the second Assise of Band 6 in Division 1 (1) ?’’) at 
Hanford Brook, St. Martin’s. 
This remarkable brachiopod is a synthetic form, showing afti- 
nities in several directions; it is thus connected chiefly with the 
Obolidez, but differs from them all in the articulate connection 
of the valves. The arrangement of the muscles is similar to 
that in Obolus and Obolella, but as regards the ventral valve is 
modified in the direction of Siphonotreta.. The position of the 
pedicle corresponds almost exactly with that of Schizambon (?) 
jissus var. Canadensis, Hall, of the Utica Slate,> but in our 
species the interior of the beak exhibits a peculiarity which 
*The boss at the centre of this valve appears to be the clay plug of the foramen of 
the ventral valve, cemented to the dorsal valve. 
+ Genera Paleozoic Brachiopoda, Hall & Clark, pl. iv., fig. 33. 
