PLATE XXXI. 
Ceratiocakis eongioauda. 
I'age 163. 
Pig. 1. The type specimen enlarged to two diameters, showing the last two somites and two of the (“.aiidal 
spines. 
Genesee shales. Bristol Center, OjitaHo county. 
CeRATIOCARIS (?) SIMPLEX. 
Page 165. 
Fig. 2. The type specimen, natural size; an internal cast of the left valve of the carajiace. 
Portage grouji. Naples, Ontario county. 
Ceratiocaris Beecheri. 
Page 104. 
Fig. 3. The type specimen, consisting of a portion of the abdomen and caudal sjiines; showing the absence 
of surface ornamentation and the short, relatively stout cercopods. 
Portage group. Son Yea, Livingston county. 
Elymocaris capsella. 
Page ISl. , 
Fig. 4. A carapace, enlai-ged to two diameters; showing the siliquoid form of the valves, the minute 
spine at the anteidor extremity of the left valve and the absence of surface ornamentation, with 
the exception of the chai'acteristic longitudinal stiise near the margins. 
Hamilton group. Tichenor's Gflen, Canandaigua Lake. 
Elymocaris siliqua. 
Page 18-2. 
Fig-. . 0 . A specimen showing the posterior portion of the caraijace with the abdomen and post-abdomen. 
The anterior jiortipn of the valves is restoj'ed in outline. 
Chemung group. Warren, JVarren county, Beniisylvania. 
Fig. 6. The separated valves of a carapace, showing- their form, the position of the eyes and the cephalic 
nodes. 
Chemung group. Warren, Wairen county, Pennsylvania. 
Tropidooaris bioarinata. 
Page 184. 
A cai-apace with the valves expanded, showing theii- form and proportions, the position of the eye- 
nodes, the character of the surface ornamentation and the size and of the rosti-al plate. 
The drawing is made from a plastei- cast taken from a natural mould of the dorsal sui-face and 
is partially restoi-ed. 
ChemvTng group. Warren, Warren county, Pennsylvania. 
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 princiiial carina. 
Chemung group. Warren, Warren county, Pennsylvania. 
The antei-ior portion of the specimen represented in fig. 7, enlai ged to two diameters; showing 
the rostral jjlate, which bears a shai-p carina along- the axial line and a fainter one on either 
side. This plate in the specimen is tilted a little to the right. 
The anterior portion of the carapace represented in fig. 8, enlarged to two diametei-s, showing the 
rostral plate somewhat displaced and tilted, the spinule at the exti-emity of the right valve, and 
the surface markings of the carapace. 
Fig. 7. 
Fig. 8. 
Fig. 9. 
Fig. 10. 
