122 J. M. Clarke—New Devonian Crustacea. 
extend anteriorly and posteriorly from the ends of the area of 
union, the anterior cleft being the shorter and its sides making 
the larger re-entrant angle. The surface of the carapace is 
marked with fine concentric ridges, as in Spathiocaris but is 
without the radiating lines of that genus. 
Of this genus I find three species, as follows: 
DIPTEROCARIS PENNA-DADALI 
Area of union of the sides of the test, or ale, extends 
about 4th the entire length of the carapace and is situated 
anteriorly. The antennal or cephalic cleft is 4d the length of 
the carapace, its sides generally straight, somewhat incurving 
toward the apex, and making an angle of radius and cireum- 
ference where they meet the margin of the carapace. Posterior 
cleft a little less than } the length of the carapace, margins 
curving slightly outward to meet the straight and parallel mar- 
gins of the carapace at an angle of 46°. imensions: length, 
50™™, width of each ala across area of union, 18™™. The sur- 
face is marked as in all of these species by low concentric 
ridges, somewhat crowded near the center, rather coarser in 
this species than in the others. 
In the illustration (fig. 1) the form is given unintentionally 
somewhat larger than actual size, and one-half of the carapace 
is restored in its proper position. 
In the light-greenish sandstones of the Lower Chemung, 
taken from a gully in the town of Canadice, Ontario Co., N. 
Y., six miles $.E. of the village of Hemlock. 
DIPTEROCARIS PROCNE. 
Area of union of the ale midway between the anterior and 
posterior extremities, and reaching less than one-third the 
length of the test. Anterior and posterior clefts of the same 
length, the margins of the anterior having a somewhat greater 
inward curve as they pass to the margin of the carapace than 
those of the posterior. 
The anterior angles made by the margins of the cleft, and 
the periphery are large—120°—but rounded. Posterior angles 
sha Sides straight, anterior curvature abrupt. Dimen- 
sions: length, 23™"; width of each ala, 9™™. 
Fig. 2 shows a carapace which has been flattened between 
the layers of sandstone, from the same locality as the preceding. 
Fig. 8 shows both a/e not flattened, but probably at nearly 
their normal angle. From the sandstones of the Middle 
Chemung at Haskinsville, Steuben Co., N. Y. 
This species differs from D. penne-Dedali in these particu- 
lars : 
