756 
Sicydiun, 689 
Siel-Smelt, 569 
Sik, 568 
Sillaginidae, 662, 653 
Sillago, 662 
Silondia, 588 
Siluranodon, 588 
Silwrichthys, 588 
Siluridae, 586, 575, 168, 251, 275, 283 ; 
barbels, 154; intestinal respiration, 292 ; 
accessory respiratory organs, 293, 294 ; 
air-bladder, 302, 303, 305 ; sound-pro- 
duction, 356-361, 363; connexion of 
the air-bladder and auditory organ, 389, 
390; nests, 416; protection of young, 
593 
Silurinae, 588 
Silurodon, 588 
Silurus, 588, 342; S. glanis, 592, 593, 
358 
Silvestri, 594 
Simenchelys, 601; S. parasiticus, 603 
Simple Ascidians, 35, 36 f., 39 f., 70, 71, 
110 
Sinipercu, 659 
Siphons, 43, 53 
Siphonognathus, 674 
Siphonostoma, 634; 8S. typhle, protective 
coloration, 172 
Sirenoidei, 749 
Sisor, 588, 589 
Skates = Raia, q.v. 
Skeleton, of Enteropneusta, 14; of Am- 
phioxus, 119; of Fishes, 193 f. 
Skin, of Cyclostomata, 182; of Fishes, 182 
Skull, composition of, 206; development, 
206; Scylliwm canicula, 207, 208 ; 
Salmo salar, 211, 212, 213, 214; 
Cyclostomata, 216 f.;  Petromyzon 
marinus, 216 f., 217; Bdellostoma, 
220 f., 220, 221; Elasmobranchii, 222 f. ; 
Notidanus cinereus, 222; Chimaera 
monstrosa, 223; Chondrostei, 224 f. ; 
Sturgeon, 224 ; Polyodon, 225 ; Crosso- 
pterygii, 226 f.; Polypterus, 227 ; 
Holostei, 228 f.; Teleostei, 229 f. ; 
Dipnoi, 231 f.; Protopterus, 231 f., 232; 
Lepidosiren, 231 f., 233 
Sluiter, 38 
Smelt, 568, 411 
Smitt, 569 n., 714 n. 
Social Ascidians, 71 
Sole, 687 
Solea, 687, 685; S. vulgaris, 686, 687 
Solenocytes, 29, 126, 127 
Solenognathus, 634 
Solenorhynchus, 634 
Solenostomidae, 633, 626, 627, 628 ; mar- 
supial pouches, 416 
Solenostomus, 633 
Soleotalpa, GS7 
Sollas, I., 522 
INDEX 
Sollas, W. J., 522 
Sorensen, 355, 590 n. 
Sorubim, 588, 361 
Sosia, 588 
Sound-producing organs, 355 f. 
Spalt-papillen, 384 
Spaniodon, 563, 564 n. 
Sparidae, 664, 654, 303, 389; teeth, 251 
Sparisoma, 674 
Sparnodus, 665 
Sparus, 665 ; S. unicolor, 665 
Spathiurus, 543 
Spathodactylus, 561 
Spengel, 5, 7, 8, 13 n., 16, 17, 18 n., 19 
Spengelia, 17, 5, 6 
Spermatozoa, 413 
Sphaerodon, 665 
Sphenacanthus, 445 
Sphenocephalus, G56 
Sphyraena, 642 
Sphyraenidae, 642, 637 
Sphyraenodus, 678 
Sphyrna, 449, 153; liver, 272; fossil, 
450; distribution, 449; .S. madleus, 
266; spiral valve, 266, 267 ; S. tiburo, 
450; S. tudes, 449; S. zygaena, 450 
Sphyrnidae, 449 
Spinacanthus, 723 
Spinachia, 630; S. vulgaris, 631 
Spinacidae, 454; photophores, 179; fossil, 
456 
Spinal cord, 367 
Spinal nerves, 378 
Spinax, 455 
Spinivomer, 603 
Spiny Dog-Fishes, 455 
Spiracle, 279, 283 
Spiracular pseudobranch, 279, 284; in 
Teleostomi, 284 ; blood supply, 335 
Spiral valve, 264 f. 
Spix, 558 n. 
Spleen, 342 
Spoon-Bill, 491 ; = Polyodon, q.v. 
Sprat, 564 
Squaliobarbus, 5S2 
Squaloraia, 468 
Squaloraiidae, 468 
Star-gazers, 155 
Starks, 627 n. 
Steatogenys, 579 
Steenstrup, 36, 685 n. 
Stegophilus, 89 ; S. insidiosus, 594 
Stegostoma, 446; S. tigrinum, 446 
Steindachneria, C47 
Steinegeria, 68:2 
Stenodus, 565 
Stephanoberycidae, 629, 606 
Stephanoberyx, G19; S. gillii, 620; 8. 
monae, 620 
Stereobalanus, 17, 5; S. canadensis, 16, 17 
Stereolepis, 659, 660 
Sterlet, 493 
