PALEONTOLOGY OF NEW YORK. 



,■[■. 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. 



•eiinen of this species has been folded and the valves slightly 

 irated 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. 



Nominal and caudal parts unknown. 



Distribution. Hamilton group. But a single specimen of this species has 



, and this is from the shales above the Encrinal limestone, at the 



id tails of Tichenor's Glen, Canandaigua Lake, associated with Echino- 



punrtata, Rhinocaris columbina, R. scaphoptera, Phacops rana, Proetus macro- 



rephalus, Pro, tus Rowi, Dalmanites Boothi and Homalonotus Dekayi. 



Elymocaris siliqua. 



PLATE XXXI, FIGS. 5,6, 



cbbb. CeratiocaridjB from the Chemung and Waverly groups, etc. Second Geol. 

 ■ .. vol. PPP, p. 13, pi. ii, figs. 1 and 2. 1884. 

 ' - W '., i:i> and Joses. Third Etept. Committee on Fossil Phyllopoda of the 

 ozoic Rocks, p. 3">. 1885. 



HALOTHORAXelongate-sub-rhomboidal or siliquiform in outline; hinge-line 



raight, somewhat shorter than the greatest length of the valves ; length 



to twice the width. Anterior extremity acutely angled, rounding 



ra P idl y '" ,1 "' ventral margin, which for a short distance is nearly parallel 



The postero-ventral extremity is broadly rounded, the 



Irving thence forward, and at the hinge slightly backward again, 



harp angle at that point. The margin is slightly thickened and 



sharp carina on the anterior and ventral edges, becom- 



oolete posteriorly. Surface evenly convex, sloping a little more 



abruptly toward the hinge than toward the ventral margin. 



