SUBJECT AND AUTHOR INDEX 
VOLUME XVII 
Abbe, Cleveland, referred to . 198 
Agelacrinus Cincinnatensis, supporting surface of 406 
^‘Agelacrinidae and Lepadocystinae, with descriptions of Thresherodiscus 
and Brockocystis.” By Aug. F. Foerste 399-487 
Agelacrinites and Lepidodiscus, Devonian, solar curvature in the .......... 406 
Agelacrinites and Lepidodiscus, use of the generic terms 431 
Agelacrinus austini, sp. nov. . 444 
Agelacrinidae, Devonian and Carboniferous, floor plates of. 416 
Agelacrinidae, location of the anus in . . 425 
Agelacrinidae, Ordovician, character of surface used for support by ...... . 401 
Agelacrinidae, Ordovician, description of several 431 
Agelacrinidae, origin of ambulacral system of 425 
Agelacrinus, central part of aboral surface 409 
Agelacrinus faberi, Miller 441 
Agelacrinus holbrooki, James 446 
Agelacrinus, Ordovician species referred to, floor plates of . 417 
Agelacrinus, ornamentation of the surface of the thecal plates. 426 
Agelacrinus Pileus, central or substomial cavity of. . 426 
Agelacrinus Pileus, orientation of, on sloping supports 401 
Agelacrinus, vertical ridges on plates of inner band of peripheral ring 408 
Agelacrinus vetustus, sp. nov. . . . , 439 
Agelacrinus warrenensis, James 448 
Agelacyinas, anal pyramid. 424 
Air currents, causes of, in Ohio . 195 
Allegheny formation. 390 
Ambulacral rays, basal extensions of lateral covering plates of 422 
Ambulacral rays, cause of reversal of curvature 404 
Ambulacral rays, cover plates of. 412 
Ambulacral rays, curvature of 403 
Ambulacral system, trimerous origin of 412 
Anniversary of the founding of the Denison Scientific Association. 203 
Anticyclonic ares in Ohio 196 
Apiocystites tencumsethi, Billings, genotype 469 
Archinacelia clochensis, sp. nov. 308 
Archinacella pulaskiensis, sp. nov. . 309 
Arkona, lake. 245 
Austinella scovillei, Miller. 130 
Austinella whitfieldi, Wincheil 131 
Brock, Dr. R. W., referred to ; ... 247 
Brockocystis clintonensis, Parks 473 
Brockocystis, gen. nov 468 
489 
