688 



INVEETEBRATA 



Sabellitormia, 128, 154 



Sabinea, Myais larva of, 215 



Sacculi, {oimationo{,mAntedon rosacea, 552 



Sagartia jjaradtica, 85 



Sagitta bipunctata, development of, 428-435 



Salamander, changes induced in by changes 



in environment, 651 

 Salivary glands, formation of, in Callidiiui 

 russeola, 424 ; in Loligo, 358, 364 ; in 

 Peripaius capensis, 175 

 Salpa, 637, 639, 640 ; development of, 635, 



636 

 Scaphopoda, 291 ; ancestors of, 368, 369 ; 



development of, 325-329 

 Scarabaeidae, 277 

 Schizocoele, formation of, in Polygordins 



appendicuiatits, 150 

 Schizopoda, 177, 185, 192, 202, 210, 213, 



216, 218 

 Scirtopoda, 418 

 Scleroblasts of Grantia, 43 

 Scoleciformia, 128, 153 

 Scolopendra, 285 ; development of, 281-284 

 Scorpion, 221 ; development of, 239-241 

 Scorpionidea, 221 



Scutum, formation of, in Cirripedia, 202 

 ScyUarus, 214 



Scyphistoma, 72, 75 ; of Aurelia, 70 

 Scyphozoa, 78, 79, 96, 166, 661 ; develop- 

 ment of, 67-76 

 Sea-anemone, delinition of, 87 

 Sea-spiders, 242 

 Sea-urchin, eggs of cross - fertilized with 



foreign sperm, 17 

 Second maxilla in Astacas, 186 

 Second maxillary segment in Bonacia, 252 

 Second polar body, definition of, 9 

 Second somatoblast in segmenting egg of 

 Dreissensia, 335 ; in segmenting of Nereis, 

 156 

 Secondary body-cavity, equivalent to ooelom, 



165 

 Secondary dorsal organ, formation of, in 



Donacia, 247, 259 

 Secondary germ - cells, formation of, in 



Doiuicia, 263 

 Secondary gill-slits, formation of, in larva of 



Amphioxus lanceolatiis, 604 

 Secondary madreporite, formation of, in 



Synapta digitata, 539 

 Secondary mesenchyme, formation of, in 



Ophiothrix fragilis, 487 

 Secondary mesoderm, formation of, in egg of 



Astacus, 181 

 Secondary radial plates, formation of, in 



Antedon rosacea, 556 

 Secondary stomodaeum, formation of, of 



Callidina russeola,, 423 

 Secondary stone - canals, formation of, in 



Antedon rosacea, 557 

 Secondary troohoblasts, formation of, in 

 embryo of Crepidula, 321 ; in embryo of 

 Fiona, 321 ; in embryo of Patella, 297 : 

 in embryo of Phascolosmna, 375 



Secondary yolk pyramids, formation of, in 



egg of Astacus, 183 

 Segmentation-cavity, 165 

 Segmentation of coelom of Asteriiia gibbosa, 



472, 473 

 Segmentation of the egg, definition of, 27 

 Segmentation of the egg of Agelena, 223 ; 

 o{ Amphioxus lanceolatus, 586, 687, 588 ; 

 of Antedon rosacea, 545 ; of Ascaris 

 megalocephala, 440-443 ; of Astacus, 179, 

 180; oi Asterias, 460; oi Aurelia aurita, 

 68 ; of Balanoglossus clavigerus, 570 ; of 

 Beroe, 89-92; of Branchipus, 194; of 

 Callidina russeola, 419-421 ; of Cere- 

 bratuhis lacteus, 119 ; oi Cucumaria pland, 

 541 ; of Cynthia partita, 612-614 ; of 

 Dentaliuvi, 326-328 ; of Dolichoglossus 

 pusillus, 583 ; of Donacia and of Dory- 

 phm-a, 246 ; of Dreissensia, 333-338 ; of 

 Mchinus esculentus, 506, 507 ; of £u- 

 phausia, 192 ; of Geryonidae, 67 ; of 

 Holothuria tubulosa, 541 ; of Julus, 284 ; 

 of Lepas, 195 ; of Macrobiotus, 243 ; of 

 Membranipora, 387 ; of Nephelis, 160 ; 

 of Ophiothrix fragilis, 486 ; of Pallene, 

 243 ; of Paludina, 310 ; of Patella, 292- 

 295 ; of Pedicellina, 398 ; of Peripatus 

 capensis, 170 ; of Phasoolosoma, 373-375 ; 

 of Planocera inquilina, 104-109; of 

 Polygordius, 131-139 ; of Polyphemus, 

 193 ; of Pyrosoma, 632 ; of Sagitta 

 bipunctata, 428, 429 ; of Salpa, 635 ; of ■ 

 Scolopendra, 281 ; of the Scorpion, 239 ; of 

 Sepia, 354 ; of Sycandra raphanu^, 37, 

 38 ; of Synapta digitata, 530 ; of Fere- 

 bratulina septentrionalis, 408 ; of Tiibu- 

 laria mesemb7-yanthemum, 54 ; of Urticina 

 crassicornis, 77 



Segmentation of mesoderm, cause of, in 

 Annelida, 165 



Segments, formation of, in embryo of 

 Agelena, 225 



Sense-tentacle, formation of, in Aurelia, 72 



Sensory-plate of larva oi Asterias, 461 



Scijia officinalis, 353, 354, 366 



Septa, formation of, in Caryophyllia cyathus, 

 87 



Septal funnels, formation of, in larva of 

 Aurelia, 70 



Serosa, formation of, in embryo of Donacia, 

 247 ; in embryo of Doryphora, 261 ; in 

 embryo of Lepisma, 265 ; in embryo of 

 Machiles, 265 ; in embryo of the Scorpion, 

 240 



Serpulidae, 416, 520 



Sertularia, development of gonophore bud of, 

 62 



Sex-chromosomes, 13, 15 



Sexual germ, definition of, 2 



Shell, formation of, in Acmaea, 304 ; in 

 Dentalium, 329 ; in Dreissensia, 339 ; in 

 Fissurella, 305 ; in Haliotis, 305 ; in 

 Loligo, 357 ; in Cyphonautes larva of 

 Menibranipiora, 392 ; in Nautilis, 357 ; 



