182 
PALEONTOLOGY OF NEW YORK. 
tion, however, is more posterior and ventral than the optic node in Elymo- 
caris siliqua. 
The ornamentation consists of minute, elevated, anastomosing lines, most 
distinctly seen near the ventral margins. 
The type specimen of this species has been folded and the valves slightly 
separated along the hinge, the right valve protruding somewhat beneath the 
ventral margin of the left. The left valve measures 13.5 mm. in length, 
and 5 mm. in width. 
Abdominal and caudal parts unknown. 
Distribution. Hamilton group. But a single specimen of this species has 
been noticed, and this is from the shales above the Encrinal limestone, at the 
second falls of Tichenor’s Glen, Canandaigua Lake, associated with Echino- 
caris punctata, Rhinocaris columbina, R. scaphoptera, Phacops rana, Proetus macro- 
cephalus, Proetus Rowi, Dalmanites Boothi and Homalonotus Dekayi. 
Elymocaris siliqua. 
PLATE XXXI, FIGS. 5, 6. 
BJymocans siliqua, Beecher. CeratiocaridfE from the Chemung-and Waverly groups, etc. Second Geol. 
Surv. Penna., vol. PPP, p. 13, pi. ii, figs. 1 and 2. 1884. 
Elyinocans siliqua, Etheridge, Woodward and Jones. Third Rejit. Committee on Fossil Phyllopoda of the 
Palaeozoic Rocks, p. 35. 1885. 
Cephalothorax elongate-sub-rhomboidal or siliquiform in outline; hinge-line 
straight, somewhat shorter than the greatest length of the valves; length 
equal to twice the width. Anterior extremity acutely angled, rounding 
rapidly to the ventral margin, which for a short distance is nearly parallel 
to the dorsal line. The postero-ventral extremity is broadly rounded, the 
margin curving thence forward, and at the hinge slightly backward again, 
making a sharp angle at that point. The margin is slightly thickened and 
elevated into a low, sharp carina on the anterior and ventral edges, becom¬ 
ing obsolete posteriorly. Surface evenly convex, sloping a little more 
abruptly toward the hinge than toward the ventral margin. 
