CRUSTACEA. 
201 
abdominal cleft rapidly divergent. The surface is ornamented with concentric 
lines or ridges as in the associated species. 
This species differs from Dipterocaris Proem in its more abrupt anterior mar¬ 
ginal curvature, more anterior isthmus and the greater relative length of the 
abdominal cleft. The dimensions of the specimen are 50 mm. in length and 
18 mm. in width to the axial line. 
Distribution. Portage group. In the upper sandstones at Canadice, Ontario 
county. 
Dipterocakis Procne. 
PLATE XXXV, PIGS. -Ib-il. 
Dipterocaris Procne, Clarke. Amer. Jouv. Science, Third Series, vol. xxv, p. 122, tigs. 2 and 3. 1883. 
Diptm-ocaris Procne, Jones and Woodward. Geol. Mag., Dec. iii, vol. i, No. 8, p. 349. 1884. 
Dipterocai'is Procne, Etheridge, Woodward and Jones. Second Kept. Committee on Fossil Phyllopoda of 
the Palaeozoic Rocks, p. 11. 1884. 
Dipterocaris Procne, Etheridge, Woodward and Jones. Third Kept. Committee on Fossil Phyllopoda of 
the Palaeozoic Rocks, p. 3. 1885. 
Carapace ovate or sub-quadrate in general outline. Surhice normally elevated 
along the dorsum and broadly rounding to the sides. Cephalic cleft very 
broad and short, extending one-fourth the length of the shield; abdominal 
cleft narrower and longer. The isthmus or the area of the union of the al(E is 
situated somewhat anteriorly and has a length less than one-third the lengtii 
of the carapace. The angles made by the margins of the anterior cleft and 
the periphery are large and obtuse, the posterior angles sharper. 
Surface ornamented by regularly concentric lines or ridges which make a 
slight retral bend at the margins of the cleft. An uncompressed individual 
has a length of 25 mm., and a width of 19 mm. 
Distribution. Portage group. In the upper portion of the formation in the 
township of Canadice, Ontario county, and in the sandstones of the Chemung 
group 1,000 feet higher at Haskinsville, Steuben county. 
