aied 
1895. } NEW YORK ACADEMY OF SCIENCES. 135 
Horizon and locality. Olive green shales of Assise 2 at Han- 
ford Brook. This is the common species of Assise 2. 
Varieties. Among the examples from Assise 2 are young 
shells which by their three-cornered shape resemble B. trian- 
gula (see below); these may be distinguished from that species 
by the larger and more depressed lunule near the cardinal area, 
and by the characteristic sculpture. Other forms by their more 
elevated posterior half and shorter valves approach B. tinea, but 
a comparison with the type of that species serves to separate 
them. ; 
This species (B. planata), is of interest as the companion of 
the Foraminifera described on a previous page; where they are 
most abundant B. planata is the prevailing Ostracod; the asso- 
ciation may indicate that this type of Ostracoda lived in the 
open sea and was not so dependent on shore conditions as some 
others. 
BEYRICHONA TRIANGULA hn, sp. Pl. vii., fig. 5. 
Subtriangular, 1 rather flat with an abrupt anterior slope. The 
valve is bordered by a narrow marginal rim. Posterior margin 
nearly straight, anterior moderately curved, the lower corner of 
the valve bluntly rounded. Ocular ridge prominent. 
Seupture. This species has a fine granulation like B. papilio. 
Size. Length 3} mm.; height 3 mm. : 
Horizon and locality. Occasionally in the shales of Assise 2, 
but more frequent in the sandstones of Assise 3. Scarce. 
This species differs from the others except B. papilio in its 
triangular form and the obsolescence of the flattened lunate 
area at the upper side of the valve; from B. papilio it differs in 
being less abruptly pointed below, in having a marginal fold, 
and in the absence of the sharp thread-like posterior cardinal 
ridge possessed by that sjecies. 
BEYRICHONA OVATA n. sp. Pl. vii., fig. 8. 
Transversely ovate, hinge-line short, not much more than half 
of the length of the valve; valve broadest one-quarter from the 
top, thence gradually tapering to an obtuse point; the valve is 
bordered by a narrow but distinct marginal fold; the ocular 
ridge is rather broad, the muscular depression subcentral, near 
the hinge-line, but not extending to it. ; 
Sculpture. Obscure, the surface where it is preserved is min- 
ute granulate. 
Size. Length 24 mm.; height 4 mm. 
Horizon and en Olive grey shales of Assise 2, at Han- 
ford Brook. Rare. 
