INDEX 



663 



Sigma {a slender rod-like spicule curved in 

 the shape of the letter C), 220, 222 



Sigmaspire (a slender rod -like spicule 

 twisted through about a single revolu- 

 tion of a spiral, and consequently having 

 the form of a C or an S according to the 

 direction in which it is viewed), 222 



Siliceous plates, of test of Ehizopods, 29, 

 53 f. 



Siliceous skeleton of Heliozoa, 71, 74 ; of 

 Eadiolaria, 76 f. ; of Siliooflagellata, 110; 

 of Sponges, 171 f., 175 f., 195 f. 



Silicified cell-wall of some Dinoflagellates, 

 130 



Silioispongiae, 195, 197 



Siliooflagellata, 86, 110, 114 



Sillcworm infested by disease p^brine, due 

 to Nosema homhycis, 107 



Simpson, on life-cycle of Ciliata, 148 n. 



Siphon, of Echinus escuUntus, 516 ; of 

 EcMnarachnius parma, 546, 547 



Siphonia, Z15 



Siphonoglyph, 334, 334, 369, 410 



Siphonogorgia, 349 



Siphonogorgiidae, 349 



Siphonophora, S97 f. ; dactylozooids, 299 ; 

 food, 304 ; gastrozooids, 299 ; gono- 

 zooids, 302 ; hydrophyllia, 300 ; life- 

 history, 302 ; nectooalyces, 298 ; pneu- 

 matophore, 300, 307 f. ; stolon, 301 



Siphonozooids, 332 ; of Pennatulacea, 359 



Sipunculidae, 576 



SipuncMlus, 563 



Skeleton, intermediate or supplemental 

 of Perforate Foraminifera, 59, 63, 66 ; 

 of Heliozoa, 71, 74 ; of Raphicliophrys, 

 74 ; of Eadiolaria, 76 f., 77 f., 81 f., 84 ; 

 of Spumellaria, 77, 77, 83 ; of Acti- 

 nomma asteracanthion, 77 ; of Acan- 

 tharia, 76 f., 78, 80, 82 ; of Xiphacantha, 

 78 ; of Dorataspis, 80 ; of Nassellaria, 

 76, 78, 82, 83 ; of Lithocercus annu- 

 laris, 82 ; of Theoconus, 80 ; of Phaeo- 

 daria, 76, 79, 82, 84, 85 ; of Aidac- 

 tiniwn actinastrmn, 82 ; of Ohallen- 

 geridae, 85 ; of PharyngeUa, 85 ; of 

 Ilaeckdiana, 85 ; of Tuscarora, 85 ; of 

 Diatomaoeae, 84 ; gelatinous, of Volvox, 

 126 — see also Shell, Test, Theca— of 

 Asterias rubens, 434 f. ; of disc of 

 Ophiuroidea, 493 ; internal, of EcMna- 

 rachnius parma, 545, 548 ; of Clypea- 

 stroidea, 548 ; of Laganum, 548 ; of 

 Clypeaster, 548 ; oi Echinooyamus, 548 ; 

 of Echinanthidae, 549 ; of Laganidae, 

 549 ; of Holothuria nigra, 560 ; of 

 Holothuroidea, 569 ; of Aspidoohirota, 

 569 ; of Dendrochirota, 569 ; of Elasi- 

 poda, 569 ; of Molpadiida, 569 ; of 

 Synaptida, 569 ; of calyx and arm In 

 Crinoidea, 588 



Sladen, on classification of Asteroidea, 460 



Sleeping-sickness, 120 



Snow, red, 125 



Solaster, 453, 455, 463; fossil, 475; S. 

 endeca, 463 ; S. papposus, 463 



Solasteridae, 453, 455, 458, 46S, 466 



Solenocaulon, SSO ' 



Sollas, I. B. J., on Sponges, 163 f. 



Sollas, W. J., on Sponges, 165 n., 168, 

 172 n., 176 n., 183 n., 207 n., 208, 

 212 n., 215 n., 216, 219 n., 233 n., 

 234 n., 238 n. ; on Palaeodiscus, 557 



Solmaridae, 296 



Solmaris, S96, 297 



Soluble substances in greater or less con- 

 centration, effect on protoplasm, 7 f. , 

 22 f. 



Sore, Oriental, 121 



Spallanzani, on origin of organisms of 

 putrefaction, 43 



Spanioplon, 223 



Sparshall's discovery of Nociiluca, 135 



Spatangidae, 554, 559 



Spatangoidea, 529, 549 f., 556, 559, 561, 

 577 



Spatangus, 553, 565 ; S. ptirpureus, 655 ; 

 *Si. raschi, 555 



Specialisation in Metazoa and Volvox com- 

 pared, 129 f. 



Specific gravity of living protoplasm, 1 3 n. 



Spencer, Herbert, on limit of growth, 23 



Spencer, W. B., on Hydroids, 271 n., 279 



Spencerian, fission at limit of growth, 23 ; 

 rhythm, 30 f. 



Sperm, Spermatozoon, 17, 31, 33 f. ; = 

 spermogametes, 33 ; penetration of 

 ovum by, 34 ; rheotaxy of, in Mammals 

 and Sauropsida, 34 ; of Sporozoa, 18 ; 

 of JPterocephahis, 99, 108 n. ; of Stylo- 

 rhynchus, 99, 100 ; of Coccidium, 100, 

 101 f. ; of Acystosporidae, 104 f. ; of 

 Sarcocysiis tenella, 108 n. ; of bisexual 

 Protozoa and most Metazoa comparable 

 with riagellata, 109 ; of Volvox gldbator, 

 127 f. ; of Eudorina, 129 



Spermatogone (=a brood -mother -cell, 

 whose ofTspring are sperms) of Cocci- 

 diaceae, 100 f.; of Volvox glohator, 127f. ; 

 of Eudorina, 129; of Acystosporidae, 

 104 f. 



Spermatozoon, 17, 18— see also Sperm 



Sperosovia, 536 



Sphaeractinia, 283 



Sphaerechinus, 5S9, 540, 541 ; 5. cjranu- 

 laris, 541 



Sphaerdla, 111 ; S. lacustris, 126 ; S. 

 nivalis, 125 ; S. plupalis, 125 f., 126 



Sphaerellaria, 77, 77 ; geological occurrence 

 of, 88 



Sphaeridium, ot Strongylocentrotus, 523 ; of 

 Echinus escuUntus, 524 ; of EcMn- 

 arachnius parma, 545 ; of Echino- 

 cardium coi^daiwin, 551 



