30 
BULLETIN OF THE LABORATORIES 
AVICULA (LEPTODESMA) SCUTELLA, Her. 
(Plate V, Fig. 6, Vol. III. Plate IV, Figs. i6, 17.) 
[See Vol. Ill, p. 59.] 
Shell small, obliquely semi-oval, hinge-line equalling the greatest 
length, height and length nearly equal; posterior wing rather large 
flat, posterior margin slightly concave, nearly at right angles to hinge- 
line ; anterior ear very small, sub-acute, depressed, nearly covered by 
the acutely projecting sub-anterior beak ; umbonal region abrubtly 
convex, rapidly expanding toward the broad lower portion of the shell, 
which is marked by concentric striae. Freestone of middle Waverly. 
Length of hinge, 6 mm., height, 6.5 mm. 
AVICULA ? S UB-S PAT U LATA, Sp. n. 
(Plate V. Fig. ii; Vol. Ill, Plate III, Fig. 6.) 
This species which is quite common in the lower part of division 
hi at Newark seems to differ widely from any associated species and, 
though its hinge is unknown, its general form associates it with carbon- 
iferous species referred to Avicula. Shell slightly oblique, forming an 
angle of about 25° with a line perpendicular to the hinge; hinge short, 
contained in the height about two and one-half times ; posterior wing 
flat, obtuse, rather small, anterior ear very small almost covered by 
the sub-anterior beaks; greatest anterior projection of anterior margin 
near the middle of the height, posterior outline gently concave above, 
convex below; surface slightly convex, grooved and striate. 
Length of hinge, 85 mm., oblique height along umbonal promi- 
nence, 21 mm., greatest length, 15 mm. 
EDMONDIA SULCIFERA, Sp. n. 
(Plate V, Fig. i, 2.) 
This fine species is most nearly related to E. burlingtonensis, but 
becomes much larger than the Ohio representatives of that species, the 
form also is less oval and the anterior hinge angle more prominent. 
Shell longitudinally sub- oblong, once and a half as long as high, 
moderately convex; posterior margin a very slight curve oblique to 
the rather long cardinal line, which extends in front of the beak to 
meet the more rapidly curved anterior margin ; lower margin nearly 
