DEVONIAN FAUNAS. 379 
terior auriculation convex, limited posteriorly by a distinct, broadly- 
rounded sinus, its anterior margin rounded; posterior wing large, 
nearly flat, rather sharply-defined by the posterior umbonal slope, its 
posterior margin concave and its posterior extremity angular. Surface 
of the left valve marked by moderately coarse, radiating coste which 
alternate more or less irregularly with finer ones, the alternation being 
more conspicuous upon the posterior portion of the shell; also marked 
by concentric lines of growth, which give to the surface a reticulate 
appearance. Upon the wings the markings are less conspicuous than 
upon the body of the shell. Right valve not seen. 
The dimensions of an average specimen are: height, 19 mm.; ex- 
treme length, 34 mm. 
Remarks.—This species has been observed only in the Greenwood 
lake locality, where it occurs quite commonly. The specimens are all 
internal casts, so the surface markings are not so conspicuous as upon 
the external surface of the shell. The proportions and general form of 
the specimens seem to be most like authentic specimens of the New 
. York Hamilton species, A. decussata, but none of the New Jersey 
specimens have been observed to attain as large a size as the larger 
individuals of that species, and the anterior auriculation is more con- 
spicuous than is usually, but not always, the case in the New York 
specimens. 
DESCRIPTIONS OF SPECIES IN THE FAUNAS OF THE MONROE SHALE 
AND BELLVALE FLAGs. 
MOLLUSCOIDEA. 
BRYOZOA. 
FENESTELLA? sp. undet. 
A few specimens of fenestelloid bryozoans have been collected from 
various localities in the Monroe shales of New Jersey, but none of 
them are in a proper state of preservation, even for accurate generic 
determination. 
