180 REPOKX — 188». 



The groupings of families, genera, &c., are as follow: — 

 I. Phtllocabida. 



A. Ceratiocarid^. 



I. Ceratiocaris, McCoy, 1849. Occurring in the Genessee and Portage 

 formations. 



1. C. longicauda. Hall, p. 163, pi. 31, fig. 1. 



2. G. Beecheri, Clarke, p. 164, pi. 31, fig. 3. 



3. C. (?) simplex, Clarke, p. 165, pi. 31, fig. 2. 



II. JEcldnocaris, Whitfield, 1880. Occurring in the Hamilton, Portage, 

 and Chemung formations. 



1. E. punctata, Hall, p. 166, pi. 27, fig. 10 ; pi. 28, figs. 1-7 ; pi. 29,. 

 figs. 1-8. Prof. Hall prefers to keep punctata rather than armata 

 for the specific name (p. 170) : see our Third Report, 1885, p. 360. 

 The Mandibles of Phyllocarida are treated of at pp. 170, 171 ;. 

 pi. 30, figs. 13-19. 



2. E. Whitfieldi, Clarke, p. 172, pi. 29, figs. 20, 21. 



3. E. condtjlepis, n. sp., p. 173, pi. 29, figs. 14-17. 



4. E. socialis, Beecher, p. 174, pi. 30, figs. 1-12. 



5. E. sublcevis, Whitfield, p. 176, pi. 29, figs. 11-13. 



6. E. pustulosa, Whitfield, p. 178, pi. 29, figs. 9, 10. 



7. E. multinodosa, Whitfield, p. 180, pi. 29, figs. 18, 19. 



The Equisetides Wrightiana, referred by Woodward and Jones to 

 Echinocaris (Third Report, 1885, p. 360), is provisionally placed by 

 Prof. Hall with Stylonurus, by reason of the character of the spinona 

 elevations, pp. 161, 162. 



III. Eltmocakis, Beecher, 1884. Occurring in the Hamilton and 

 Chemung formations. 



1. E. capsella, n. sp., p. 181, pi. 31, fig. 4. 



2. E. siliqua, Beecher, p. 182, pi. 31, figs. 5, 6. 



rV. Tropidocaris, Beecher, 1884. Occurring in the Hamilton and 

 Chemung formations. 



1. T. hicarinata, Beecher, p. 184, pi. 31, figs. 7-12. 



2. T. interrufta, Beecher, p. 185, pi. 31, fig. 13. 



3. T. alternata, Beecher, p. 186, pi. 31, figs. 14, 15. 



B. Pinacarid^. 



I. Mesothyra, n.g. Occurring in the Marcellus, Hamilton, and, 

 Portage formations. 



1. M. Oceani, n. sp., p. 187, pi. 32, figs. 1-6 ; pi. 33, figs. 4-7 ; pi. 34, 

 figs. 1-5. Separated from M. (formerly Dithyrocaris) Neptuni, 

 Hall, on account of some differences in the caudal appendages. 



2. M. Neptuni, Hall, p. 191, pi. 32, fig. 7 ; pi. 33, fig. 1. 



3. M. spumcea, n. sp., p. 193, pi. 32, figs. 8, 9 ; pi. 34, fig. 2. 



4. M. {Dithyrocaris ?) Veneris, n. sp., p. 193, pi. 33, fig. 3. 



[II. Dithyrocaris, Scouler, 1843.] In the Hamilton formation. 

 1. D. Belli, Woodward, p. 184 (Gaspe). 



C. Rhinocarid^. 



I. Rhinocaris, n.g. (J. M. C.) Occurring in the Hamilton formation. 

 Eh. columbina, n. sp., p. 195, pi. 31, figs. 16-21. 

 Rh. scaphoptera, n. sp., p. 197, pi. 31, figs. 22, 23. 



