J. M. Clarke—New Devonian Crustacea. 123 
a, The anterior marginal curvature is more abrupt and 
shorter. 
6. The area of union is larger and medially situated, 
¢. The cephalic and abdominal clefts are of the same length. 
d. The individuals are, as far as observed, much smaller. 
These details of difference are all well shown in the figures. 
bd 
ek «Ae 
AN 
a 
Di ; ; ; ve.  Dipterocaris pes-cerve. 
pterocaris Procne. Dipterocaris pes-cer ; J menaed Pp de 
DIPTEROCARIS PES-CERV2. : 
Outline of carapace elongate lanceolate, area of union of ale 
anterior, dh the Jength of the test. Cephalic cleft short, mar- 
8s divaricating at an angle of 68° in the typical specimen and 
making angles of 78° with the periphery of the test. Posterior 
cleft long and narrow, the margins making an angle of 6 with 
each other, and angles of about 23° with the periphery. pa 
Sions: length 11™", width of each ala 33”. From the sandy 
Shales of the Lower Chemung in the cutting of the Delaware, 
- eawanna & Western Railroad, at Dansville, Livingston Co., 
