206 NEW YORK STATE MUSEUM 
Description. Body medium-sized to large. Carapace semicircular, 
nearly twice as wide at base as long (length : width as 6: 11), probably 
originally quite high (as indicated by concentric wrinkles); lateral and 
frontal margins forming a continuous circular curve, when the carapace 
is flattened; the thickened edge scalloped; posterior margin straight and 
transverse, genal angles nearly rectangular; compound eyes relatively 
small (one seventh the length of carapace), consisting of a bean-shaped, 
very prominent ocular node and narrow reniform visual surface, situated 
halfway between the frontal and basal margins, far apart (three fourths 
as far from lateral margin as apart); the ocellar node prominent, in 
exact middle of carapace. 
First tergite one fifth as long as the carapace, nine times as wide as 
long. Postlateral angles truncate. Postabdomen at its anterior end about 
three fourths as wide as long and tapering to about one third of its an- 
terior width. The segments possess distinct epimera which become increas- 
ingly winglike posteriorly, on the last segments possessing sigmoidal margins. 
Ornamentation. The ornamentation of the carapace and postabdom- 
inal segments has been described above. From an exfoliated portion of 
one specimen [pl. 23, fig. 1] it is seen that the test of the marginal shield 
of the cephalothorax was furnished with wartlike, round pustules. | | 
Measurements. Carapace of type, 67 x 120 mm (as 6: 10.7); that 
of Pohlman’s type of E . giganteus soxo93 mm (as 6:11). Eyes 
in type 41 mm apart and 30 mm from lateral margin; in other specimen 
» mm long, 31 mm apart and 24 mm from margins. First tergite of this 
specimen 9.5 mm long. Postabdomen about 150 mm wide at anterior end, 
210 mm long and about 50 mm at posterior end. 
Horizon and locality. Bertie waterlitne at Buffalo. 
Remarks. A third carapace (with attached first tergite) of like dimen- 
sions with the type of the species is in the Buffalo Museum. It is note- 
worthy for the distinctness of the ornamentation of the first tergite, con- 
sisting of a narrow anterior zone of very closely arranged tubercles and the 
characteristic disklike scales which here are larger, more numerous, and 
