860 l)EscEiPTioN OF [^Poli/gasiricat 



middle portion evenly convex, but decreasing suddenly towards the 

 slightly revolute and obtuse ends. Mexico. (P. 15. f. 24, 25.) 



EiTNOTiA monodon. — Striated, elongate ; venter concave ; dorsum 

 evenly convex; constricted slightly near the rather recurved 

 ends. (P. 15. f. 27.) 



E. parallela. — Linear, strongly striated, curved, apices simply 

 rounded. North America. 



E. pileus. — Small, striated, subquadrate, as seen on the sides ; the 

 under surface is wider than the upper ; the latter slightly furrowed ; 

 ends obtuse, rather prolonged. Siberia. Fossil. 



E. lofifficornis. — Large, elongated, dorsum continuously convex; 

 extremities rather reflexcd ; venter concave ; surface marked laterally 

 by many wide costae, alternating ^vith more or less rounded or quad- 

 rate spaces, which are also striated. It is allied to E. Argus. (P. 24, 

 figs. 6 to 9.) 



E. prcerujjta. — Striated, elongate, back curved evenly and continu- 

 ously to its dilated and truncated extremities. 



E. quarternaria, — Small, narrowly linear, cui-ved; back four-toothed ; 

 apices somewhat recurved. Liberia, Cayenne. 



E. quinan'a. — Small, narrow, linear ; dorsum but sKghtly convex, 

 with five dentations ; ends rounci*,'^, Siberia, New York, Guano. 

 (P. 15. f. 39.) 



E, Sella. — Striated, dilated ; dorsum, with a central groove^ 

 bidentate ; continued as a regular ciuwe to the acute ends. 

 Cayenne. 



E. septena. — Small, narrowly linear, with seven dorsal dentations. 

 Labrador. 



E. Textricula = Epithemia Textricula (Kiitz.) Small, with paral- 

 lel sides ; back evenly convex ; convexity prolonged to the round, 

 not tapering extremities ; striee lateral, few and strong ; their inter- 

 spaces ■with fine longitudinal lines. Fossil, Iceland and Mexico. 



E. Tridentula. — Small, narrowly linear, stiiated; dorsum triden- 

 tate. Fossil, Iceland, Cayeime, and Connecticut. 



E. centralis. — Large, linear, striated, curved ; venter turgid in the 

 middle ; dorsum even ; apices enlarged, rounded. North America- 



