northern zone, i, 250 
Norway haddock, ii, 428 
Notacanthida, ii, 157 
Notacanthus, ii, 157, 532 
figure of, ii, 158 
Notzus, ii, 36 
Notagogus, li, 26 
figure of, ii, 28 
Notelops, ii, 44 
Notidiani, i, 447, 513, 519, 
526 
order of, i, 523 
Notidanoid shark, i, 438 
skull of, figured, i, 56 
Notidanus, i, 523, 524 
notochord, i, 55, 56, 509 
in Chimeras, i, 59 
in Elasmobranchs, i, 57 
Notogeneus, i, 456 
figure of, ii, 55 
Notopteride, ii, 48, 49 
Notopterus, ii, 49 
Nototheniide, ii, 501, 502, 
533, 
Notropis, i, 129, 283, 304, 
307, 311, 313; ii, 164 
figure of, i, 343, 4573 ii, 
165, 167 
Noturus, i, 180; ii, 177, 182 
Novaculichthys, ii, 390 
Novara, i, 410 
Nozawa, i, 418 
numbers of genera, i, 262 
numbfish, 
figure of, i, 185, 553 
number of vertebra, i, 202— 
204 
nuptial colors, i, 155, 156 
nuptial tubercles, i, 33 
figure showing, ii, 167 
Nystrom, i, 416 
oarfish, i, 361; ii, 472 
figure of, i, 362; li, 476 
Forgy on, ii, 473 
Glesnes, ii, 472 
Holder on, ii, 474 
Oatka Creek, i, 282 
Oblata, i, 260; ii, 348 
‘ocean currents, 
agency of, i, 242 
Ocyurus, 
figure of, ii, 337 
Odacide, ii, 388 
Odax, ii, 390 
Odontaspidide, i, 533 
Odontaspis, i, 534 
Odontoscion, ii, 355 
Odontostomus, ii, 136 
Odontotodontide, i, 576 
Odontotodus, 
figure of, i, 570 
Ogcocaphelida, ii, 551 
Index 
Ogcocephalus, 
figure of, ii, 551-553 
shoulder-girdle in, i, 88 
Ogilby, i, 408, 416 
on ragfishes, ii, 285 
oil shark, i, 524 
Oikopleura, i, 474 
ojanco, ii, 337 
okose, i, 236, 429; ii, 436 
oldwench, ii, 413 
oldwife, ii, 413 
Old World catfish, ii, 182 
olfactory lobe, 
figure of, i, 111 
Oligocottus, ii, 447, 449 
figure of, ii, 449 
Oligopleuride, ii, 36, 41 
Oligopleurus, ii, 36 
Oligoplites, ii, 272 
Oligorus, ii, 320 
ombre chevalier, ii, 108, 109 
Omosoma, ii, 284 
Omosudis, ii, 136 
Onchus, 
Agassiz on, i, 530 
fin-spine of, i, 509 
Oncobatis, i, 553 
Oncottus, i, 317; ii, 447, 449 
figure of, il, 447 * 
Oncolepis, ii, 513 
Oncopterus, ii, 489 
Oncorhynchus, i, 146, 160, 
30T, 329, 332; li, 68, 70, 
89, 94 i 
figure of, 354; li, 69, 71, 
72, 76 
ontogeny, 1, 511 
ontology, i, 63 
oopu, ii, 465 
Onychodontide, i, 602, 604 
Onychodus, i, 604 
opahs, i, 210; ii, 243 
taken by Berndt, ii, 244 
Farquhar on, ii, 244 
figure of, i, 323 
opercle, i, 7, 45 
opercula, 
used in climbing, ii, 367 
operculum, ii, 7 
Ophicepalide, ii, 370 
Ophidiide, ii, 520 
Ophidion, i, 391, 612 
Ophichthyide, i, 211; ii, 150 
Ophichthus, 
figure of, ii, 151 
Ophiocephalide, i, 103, 104; 
li, 215 
Ophiocephalus, i, 149 
figure of, i, 150 
Ophiodon, ii, 442, 518, 520 
figure of, ii, 440 
Ophioblennius, ii, 510 
Ophiopsis, ii, 26 
583 
Ophocephalus, 
figure of, ii, 370 
Opistharthri, i, 509 
Opisthocentrus, ii, 512 
Opisthoccelian, i, 49; ii, 29 
Opisthoccelus, ii, 6 
Opisthognathide, ii, 330, 359, 
499, 502 
Opisthognathus, ii, 462, 508 
figure of, ii, 360 
Opisthomi, i, 611; ii, 499, 
532-542 
Opisthomyzon, ii, 469 
Storms on, ii, 469 
Opisthonema, ii, 51, 53 
opisthure, i, 84 
Oplegnathus, i, 260 
Opsanus, ii, 525 
figure of, ii, 524 
Opsariichthys, ii, 165 
optic nerves, 
of flounders, ii, 482 
orbitophenoid, ii, 40 
orca, 1, 361, 536 
order, 
defined, i, 373 
organs of the fish, 
electric, i, 25 
of hearing, i, 119-121 
nutritive, 1, 29 
Orectolobus, i, 533 
Orestias, ii, 200 
Oregon lamprey, 
figure of, i, 496 
Oregon sucker, 
teeth of, figured, ii, 175 
Ordovician deposits, 
figure of, i, 435 
origin, 
of air-bladder, i, 98 
of fins, i, 62, 64, 67 
of lungs, i, 98 
origin of lancelets, 
Willey on, i, 484 
Orodontidz, i, 65, 66, 447, 
528 ss 
Orr, 
on external gill, i, 77 
Ortmann, i, 238, 256, 270 
map of continents, i, 270 
Orthacanthus, i, 521 
Orthodon, ii, 165 
Orthopristis, ii, 342 7” 
Orthopsetta, i, 206; ii, 489 
Orthosteechus, i, 271 
Osbeck, i, 389 
Osbeckia, ii, 414 
figure of, ii, 414 
Osborn, 
on extinction of species, i, 
239, 442 
on law of radiation, i, 296 
Osmeroides, ii, 44, 134 
