PLATE XXXI—Continued. 
Fig. 11. The right valve of a small individual, slightly broken at the anterior extremity, but showing the 
sharply angular posterior extremity of the hinge. This valve is somewhat broader posteriorly 
than that represented in fig. 7, and as it appears to be uncompressed this outline is probably 
correct for the species. 
Chemung group. Warre?i, Wamn county, Pennsylvania. 
Fig. 12. Two segments of the abdomen and a portion of the telsoh, referred with doubt to this species. 
The drawing is enlaj-ged to two diameters to show the character of the surface markings. 
Chemung group. Warren, Wamn county, Pe^insylvania. 
Tropidocaris interrupta. 
Page 185. 
Fig. 13. A right va'lve of the carapace, showing the form and surface ornamentation. 
Chemung group. Warren, Wari'en county, Peniusylvania. 
Tropidooaris alternata. 
Page 186. 
Fig. 14. An imperfect left valve, showing the numerous carinse and the nodes in the cephalic region. 
Waverly grouji. Wamn, Warren county, Pennsylvania. 
Fig. 15. Another imperfect left valve, showing the carinse and bearing the impression of plates of an 
echinoderm. 
Both this and the preceding figure have been drawn from gutta-percha impressions taken from 
natural moulds of the dorsal surface. 
Waverly group. Warren, Warren county, Pennsylvania. 
Ehinocaris columbina. 
Page 195. 
Fig. 16. A carapace which has been laterally compressed, but retains the prora. Near the dorsal margin 
is seen the line along which the carapace has been fractui’ed. The surface shows no ornamen¬ 
tation except the faint striae along the margins. 
Fig-. 17. The anterior portion of the same specimen, enlarged to two diameters to show the character of the 
prora. The carapace has been fractured near the base of the prora, but upon the dorsal sur¬ 
face the latter is continuous with the shield. 
Hamilton group. Tichenor's Glen, Canandaigua Lake. 
Fig. 18. A portion of the carapace upon which lies a very small mandible. 
The specimen is enlarged to three diameters. 
Hamilton group. Vinegar Brook Glen, Cayuga Lake. . 
Fig. 19. A fragmentary specimen, showing a portion of the carapace, three segments of the alxlomen, the 
sub-conical caudal plate and telson, -svith the cercopods. 
Hamilton group. Vinegar Brook Glen, Cayuga Lake. 
Fig. 20. The posterior portion of a large carapace, showing the character of the iiostei-ior margin. 
Hamilton group. Tichenor's Glen, Canandaigua Lake. 
Fig. 21. An impei-fect specimen retaining one side of the carapace, showing t|he last abdominal segment 
and the telson. 
Hamilton group. Eighteen-mile Creek, Erie county. 
Rhinocaris soaphoptera. 
Page 197. 
Fig. 22. A view of the left side of a cai-apace which has been crushed along a line lying to the left of the 
axis, making this side apj)ear narrower than is normal; showing the prora, the conspicuous 
lateral carina and the sui-face oi-namentation. 
Fig. 23. The anterior portion of the same specimen, enlarged to two diameters to show the character of the 
prora, which is continuous with the carapace. 
Hamilton group. Tichenor's Glen, Canandaigua Lake. 
