INDEX OF SUBJECTS. 



661 



Scypliostoma, 103 



seasonal dimorphism, 501 



Semites, 574 



septa, 107 



seise, 204, 218 



seta-sacs, 304 



sexual dimorphism, 193, 199, 241, 



395, 496 

 shell, — Amphineura, 289; Brachiop- 

 oda, 269; Cephalopoda, 343, 857, 

 360; Gasteropoda, 303, 316; Pele- 

 cypoda, 327; Scaphopoda, 323 

 shell-gland, 383 

 siphon, 304, 327, 493, 579 



siphonoglyphe, 106 



sipuncle, 358 



skeleton, — Cephalochorda, 613; Ente- 

 ropneusta, 609 



somatic cells, 44 



somatic mesoderm, 206 



spermatid, 48 



spermatocyte, 48 



spermatogenesis, 48 



spermatogone, 48 



spermatophore, 355 



spermatozoa, 44, 47 



sphsei-idia, 574 



spinning-glands, 449 



splanchnic mesoderm, 206 



splanchnocoel, 610 



spongiolin, 73 



sporocyst, 149 



statoblast, 261 



Sterrula, 55 



Stewart, organs of, 576 



stigma, 39 



stigmata,— Arachnida, 436; Tra- 

 clieata, 470; Urochorda, 633 



stoinatodasum, 105 



stomodsBum, 313 



stone-canal, 536 

 strobila, 104, 154 

 subneural gland, 623 

 Sycon, 71 

 symbiosis, 20, 83 

 syncerebrum, 379 



Tsenioglossate dentition, 307 



tapetum lucidum, 336, 440 



telolecithal, 53 



telson, 369 



testis, 44 



thorax, 488 



Tiedemann's vesicles, 557 



tissue, 41 



Tornaria, 606 



toxiglossate dentition, 308 



trachese, — Arachnida, 436; Isopoda, 



414; Tracheata, 470 

 tracheal branchiae, 491 

 trichocyst, 35 

 trivium, 572, 584 

 Trochophore, 313 

 trophopolyp, 85, 91 

 tube-feet, 537 

 tympanal organ, 496 

 typhlosole, 220, 633 



Veliger, 320 

 velum, 81, 320, 613 

 ventral plate, 326 

 vibracula. 263 

 vitellarium, 130, 155, 193 



Water- vascular system, 535 

 wax-glands, 490 

 wings, 489, 522 



Zoea, 420 

 zooBcium, 255 

 zooxanthellSB, 30 



