INDEX OF SUBJECTS. 



661 



Scyphostoma, 103 



seasonal dimorphism, 501 



Semites, 574 



septa, 107 



set*, 204, 218 



seta-sacs, 204 



sexual dimorphism, 193, 199, 241, 

 395, 496 



shell, Ainphineura, 289; Brachiop- 

 oda, 2(59; Cephalopoda, 343, 357, 

 360; Gasteropoda, 303, 316; Pele- 

 cypoda, 327; Scaphopoda, 322 



shell-gland, 383 



siphon, 304, 327, 493, 579 



siphoiioglyphe, 10(5 



sipuucle, 358 



skeleton, Cephalochorda, 613; Ente- 

 ropneusta, 609 



somatic cells, 44 



somatic mesoderm, 206 



spermatid, 48 



spermatocyte, 48 



spermatogenesis, 48 



spermatogoue, 48 



spermatophore, 355 



spermatozoa, 44, 47 



sphseridia, 574 



spiuniug-glauds, 449 



splanchnic mesoderm, 206 



splauchnocoel, 610 



spongiolin, 72 



sporocyst, 149 



statoblast, 261 



Sterrula, 55 



Stewart, organs of, 576 



stigma, 29 



stigmata, Arachuida, 436; Tra- 

 cheata, 470; Urochorda, 622 



stomatodseum, 105 



stomodaeum, 213 



stone-canal, 536 

 strbbila, 104, 154 

 subueural gland, 623 

 Sycon, 71 

 symbiosis, 20, 83 

 syucerebrtim, 379 



Tsenioglossate dentition, 307 



tapetum lucidum, 336, 440 



telolecithal, 53 



telson, 369 



testis, 44 



thorax, 488 



Tiedemauu's vesicles, 557 



tissue, 41 



Tornaria, 606 



toxiglossate dentition, 308 



tracheae, Arac-huida, 436; Isopoda, 



414; Tracheata, 470 

 tracheal branchiae, 491 

 trichocyst, 35 

 trivium, 572, 584 

 Trochophore, 213 

 trophopolyp, 85, 91 

 tube-feet, 537 

 tympanal organ, 496 

 typhlosole, 220, 623 



Veliger, 320 

 velum, 81, 320, 612 

 ventral plate, 226 

 vibracula, 263 

 vitellarium, 130. 155, 193 



Water- vascular system, 535 

 wax-glands, 490 

 wings, 489, 522 



Zoea, 420 

 zooecium, 255 

 zooxanthellse, 20 



