Plate III. 



Fig. 1. Gyr acanthus shericoodi Newberry. Chemung beds; 

 Ischua township, Cattaraugus county, New York. Drawn from 

 squeeze of spine, x 3-4. Page 114 



Fig. 2. Detail of surface ornamentation of Arthrodiran (?) 

 plates similar to those described by Newberry under the name 

 of Sphenophorus (="Oestophorus" S. A. Miller), from the 

 Hamilton limestone of Milwaukee, Wisconsin, x 2-1. Page . 207 



Fig. 3. Cladodus urbs-ludovici, sp. nov. Genesee shale 

 (~"New Albany black shale"); near Louisville, Kentucky. 

 Holotype in Museum of Comparative Zoology, Cambridge, Mass. 

 x 2-1, approximately. Page 110 



Fig. 4. Machaer acanthus sidcatus Newberry. Onondaga 

 limestone; Victor, Ontario county, New York. Re-drawing of 

 holotype figured by Hall; original in New York State Museum, 

 x 3-4. Page 114 



Fig. 5, 5o. Acantholepis sp. Corniferous limestone ; Falls of 

 the Ohio. A small, probably immature and fragmentary spine, 

 showing expanded nature of the pyramidal inserted portion. 

 The lateral and anterior faces are shown in figs. 5 and 5o re- 

 spectively, x 3-4. Page 142 



Fig. 6. Ptyctodus punctatus Eastm. Onondaga limestone 

 (Ulsterian division of the Middle Devonian) ; LeRoy, New York. 

 Functional surface of the detached tritor. x 3-4. Page 133 



Fig. 7. Coelacanthus ivelleri, sp. nov. Kinderhook lime- 

 stone; Burlington, Iowa. Flank scales, slightly enlarged, show- 

 ing spiniform ornamentation. Holotype in Walker Museum of 

 University of Chicago. Page 247 



Fig. 8. Rhynchodus major Eastm. Upper Devonian; Wild- 

 ungen, Waldeck. Left upper and lower dental plates (inner 

 aspect) arranged in natural position. The outlines of these 

 plates are copied from Jaekel, who figures them, however, in 

 inverted position, and renames the species "R[h}amphodus 

 tetrodon." x 3-4. Page 127 



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