Figures in Italics refer to pages on which descriptions are given. 



Acanthaspis, 142 



characters of genus, 144 

 Acanthaspis armata, 145, 188, 277 



decipiens, 188 



minor, 145 



pruemensis, 145 



tuberculatus, 145 

 Acanthodes, 61 

 Acanthodes affinis, 280 



orowni, labyrinth of, 266 



concinnus, 280 



gracilis, 60 



(?) pristis, US, 281 



semistriatus, 275 



sulcatus, 60 

 Acanthodians, 99 



advent of, 53 



Silurian, character of, 59 

 Acanthodidae, range of, 112 

 Acanthodii, 68, 69 



characters of order, 112 

 Acanthoossus ? pristis, 113 

 Acantholepis, 143, 144 



characters of genus, 140 

 Acantholepis fragUis, 141, 142, 277 



pustulosus, 142 

 Acanthopterygii, 68 



character of, 64 

 Acipensideridae, degeneration of, 256 

 Acknowledgments, 291 

 Actinistia, 69 



characters of suborder, 2%1 

 Actinophorus clarki, 285 

 Actinopterygii, 69 



character of order, 255 



list of, 280, 282, 285 

 Actinotrichia, 103 



Adams, F. D., cited, 264 



Administrative reports, 1 



Aetheospondyli, 69 



Agar, W. E., cited, 165 



Agassichthys agassizi, 175 



; manni, 168 



i sullivanti, 168 



Agassiz, L., cited, 168, 175, 187, 243 



mentioned, 147, 150, 242 

 Agnatha, advent of, 53 



characters of, 53 



classification of, 69 



systematic account of, 70 

 Albert coal mine, New Brunswick, 



fish remains from, 257, 2G1, 262 

 Albert county, New Brunswick, 



fish remains from, 261, 262, 273 

 Alleghany county, New York, 



fish remains from, 225, 288 

 American Museum of Natural History, 



124, 153, 250, 265, 271 

 Amia, 63 



"Amphistyly", 66, 96 

 "Anarthrodira", 170 

 Anaspida, 69, 72 



occurrence of, 74 

 Antiarchi, 69, 72 



characters of order, 74 



classification of, 56 



occurrence of, 75 

 Apateacanthus vetustus, 281 

 Apedodus priscus, 288 



relations to Holoptychius, 238 

 Appalachian district, fish remains 



from, 215, 239, 261, 281 

 "Appalachian" sea, 45 

 Archipterygium, 100 

 Arctolepis, 145 

 Arctolepis decipiens, 145 



(367) 



