PLATE XXXI. 

 Cebatiocaris longioauda. 



Page 1 

 Fig. 1. The type specimen enlarged to two diameters, showing the last two somites and two of the caudal 



spines. 



Genesee shales. Bristol Center, Ontario county. 



CeRATIOCAEIS (?) SIMPLEX. 

 Pago 165. 

 Fig. 2. The type specimen, natural size; an internal cast of the lefl valve of the carapace. 

 Portage group. Naples, Ontario county. 



Ceratiocaris Beecheri. 



Page 164. 

 Fig. 3. The type specimen, consisting of a portion oi the abdomen and caudal spines j showing the absence 



of surface ornamentation and the short, relatively stout rercopods. 

 Portage group. Son Yea, Livingston county. 



Elymocaris CAPSF.LLA. 



Page IS1. 

 Fig. 4. A carapace, enlarged to two diameters; showing the siliquoid form of the valves, the minute 

 spine at the anterior extremity of the left valve and the absence of surface ornamentation, with 

 the exception of the characteristic longitudinal stria? near the margins. 

 Hamilton group. Tichenor's Qltn, Canandaiyua Lake. 



Elymocaris siliqua. 



Page 182 

 Fig. 5. 4 specimen showing the posterior portion of the carapace with the abdomen and post-abdomen. 

 The anterior portion of the valves is restored in outline. 



Chemung group. Warren. Warren county, Pennsylvania. 

 Fig. 6. The separated valves of a carapace, showing their form, the position of the eyes and the cephalic 



nodes. 



Chemung group. Warren, Warren county, Pennsylvania. 

 Tropidooaris bioarinata. 



Page 184. 

 Fig. 7. A carapace with the valves expanded, showing their form and proportions, the position of the eve- 



nodes, the character of the surface ornamentation and the size and of the rostral plate. 



The drawing is made from a plaster cast taken from a natural mould of the dorsal surface and 



is partially restored. 



Chemung group. Warren, Warren county, Pennsylvania. 

 Fig. S. A smaller carapace, the valves of which are somewhat crushed; showing the rostral plate, one of 



the eye-nodes and the large lunate nodes on the outer edge of the principal carina. 

 Chemung group Warren, Warren county, Pennsylvania. 

 Fig. 9. The anterior portion of the specimen represented in tig. 7, enlaiged to two diameters; showing 



the rostral plate, which bears a shaip carina along the axial line and a fainter one on either 



side. This plate in the specimen is tilted a little to the right. 

 Hs.'. 10. The anterior portion of the carapace represented in tig. 8, enlarged to two diameters, showing the 



rostral plate m >mewhat displaced and tilted, the spinule at the extremity of the right valve, and 



the surface markings of the carapace. 



