640 INDEX 



Sertularia, 142; 141 



Sexual congress, see Sexual distinc- 

 tion and sexual behaviour, Mutual 

 fertilization 



Sexual distinction and sexual be- 

 haviour, of Arachnida, 452, 457, 

 461, 465; of Archiannelida, 261, 

 263; of Balanoglossus , 589; of 

 Bonellia, 268 ; of Cephalopoda, 

 523 ; of Coelenterata, 1 3 1 ; of Crus- 

 tacea, 314, 318, 324, 329, 332, 

 334, 335, 336, 337, 34,i, 343, 344, 

 355, 359, 368; of Echinodermata, 

 553 ; of Insecta, 394, 412, 413, 415, 

 420; of Myriapoda, 379, 381; of 

 Nematoda, 220 ; of Nemertea, 205 ; 

 of Onychophora, 285 ; of Panto- 

 poda, 467 ; of Polychaeta, 246 ; of 

 Protozoa, 28 ; of Rotifera, 212. See 

 also Generative organs 



Sexual reproduction, of Metazoa, 

 see Generative organs ; of Protozoa, 

 26. See also Life history 



Shape, see Body 



Shell of Crustacea, see Carapace 



Shell of Echinoidea, see Corona 



Shell glands, of Crustacea, see 

 Maxillary glands ; of Platyhelmin- 

 thes, 185 



Shell ligament, 499 



Shell types of Foraminifera, Arena- 

 ceous, 69; Imperforate, 69; Per- 

 forate, 69 



Shells, of Brachiopoda, 537 ; of 

 Crustacea, see Carapace; of Fora- 

 minifera*, 9, 67, 68, 69, 70, 70, 71 ; 

 of Mollusca*, 471, 472, 474, 475, 

 476, 477, 479, 480, 490, 491, 492, 

 494, 509, 510, 511, 515, 520, 525, 

 527-9 ; of Protozoa, 8 



Shield-shaped tentacles, 573 



Sialis, 425 



S. lutaria, 425 



Sicula, 148 



Sida, 325 



Silicoflagellata, 46 



Silicoflagellidae, see Silicoflagellata 



Silver fish, see Lepisma saccharina 



Simocephaliis , 325 



5'. sima^ 326 



Sinus system of Hirudinea, 265 



Sinuses, Haemal, of Arachnida*, 450, 

 459 ; of Arthropoda, 279 ; of 

 Crustacea, 312; of Helix, 483; of 



Lamellibranchiata, 506 ; oiLumhri- 



culiis, 260 ; oi Pomatoceros , etc., 230 



Siphon, of Echinoidea, 569; of 



Gasteropoda, 482 

 Siphonoglyphes, 159 

 Siphonophora, 133; 144, 146, 147 

 Siphonozooids, 162 

 Siphons of Lamellibranchiata, 501 

 Siphuncle, 526; 525 

 Sipunculoidea, 269 

 Sipunculus, 269, 269 

 Size of Protozoa, 4 

 Skeletal plates, of Echinoidea, 564; 



of Ophiuroidea, 562 

 Skeletogenous layer, no 

 Skeleton, External, see Corals, Cu- 

 ticle, Perisarc, Shell; Internal, see 



Internal skeleton 

 Skull of Cephalopoda, 520 

 Slimonia, 452; 453 

 Small intestine of Insecta, 390 

 Social life of Hymenoptera, 434 

 Soldiers of Isoptera, 412 ; 414 

 Solenia, 160 

 Solenocyte, 242 ; 23 

 Solidago, 396 

 Somatoblast, 250 

 Somites (body segments). Series of, 



in Arthropoda, 271, 272-3; in 



Crustacea, 292-3 ; in Polychaeta*, 



231, 232, 235, 237, 238. See also 



Tagmata 

 Somites, Mesoblastic, see Mesoderm 



segments 

 Spatangoida, 571; 570 

 Spatangus, 571 



Sperm sacs, see Seminal vesicles 

 Sperm vesicle of Chaetognatha, 544 

 Spermatheca (Receptaculum semi- 



nis), of Helix, 486 ; of Insecta, 397 ; 



of Nematoda, 218; of Platyhel- 



minthes, 185 

 Spermathecal ducts of Gasteropoda, 



486 

 Spermatic atrium, 259 

 Spermatophores, of Crustacea, 314; 



of Helix, 486; of Peripatus, 285; 



of Sepia, 522 

 Spermatozoa, of Crustacea, 314; of 



Hirudinea, 266 ; of Nematoda, 218 

 Spermiducal glands of Oligochaeta, 



254 

 Sphaeractinomyxon, 95 

 Sphaerella, see Haematococcus 



