I74 NEW YORK STATE MUSEUM 
E.lacustris Hall. Palaeontology of New York. 1859. 3: 407%, pl. 81, fig. 1-11; 
pl. 81A, fig. 1; pl. 81B, fig. 1-5; pl. 83B, fig. 3 
Not 
BE. lacustris Salter. Geol. Soc. London. Quart. Jour. 1859. 15: 235 
E.remipes Logan. Geology of Canada. 1863. p. 354, fig. 464. 
Description. Eody medium sized, ovate-lanceolate in form, robust, 
not quite four times as long as wide. 
Cephalothorax broad and short. Carapace trapezoidal, about two thirds. 
as long as wide (length: width as 6: 9-10), occupying between one fifth 
and one sixth of the whole length; broadest at the base. Its lateral margins 
are nearly straight, slightly converging forward; anterior margins gently con- 
vex forward; antelateral angles well rounded; posterior margin slightly 
concave, bent forward near the genal angles. Profile of carapace not 
observed. The lateral eyes are small, only one fifth as long.as the carapace 
or less; situated in front of the middle, twice as far apart as distant from 
the lateral margin, bean shaped, prominent; ocelli situated midway be- 
tween them. 
The preabdomen occupies about one fourth the length of the body. 
It is slightly wider (about one eighth to one ninth) than long, widening 
gradually to the fourth tergite and then decreasing again as gradually. 
The first tergite is seven and one half times as wide as long, the fourth 
only about six times. The outline of the tergites is the same as in 
E.fischeri. The sternites are also like those of that species, about four: 
times as wide as long. | 
The postabdomen occupies one third of the length of the whole body. 
The first two segments contract at the same rate as the posterior preab- 
domen, the rest more gradually to nearly one third its anterior width. The 
telson corresponds in its relative size and character to that of 
E. remipes. | 
Appendages. The cephalothoracic appendages, including the cheli- 
cerae, are well shown in several specimens. They differ but slightly from 
_those of E. remipes. 
