622 



INDEX 



Sexual organs, see Reproductive 



organs 

 Sexual reproduction, see under 



various types 

 Shank, 5 



Shell, 396 ; larval, 410 

 Shell of egg, 469, 564 

 Shell-gland of mussel-embryo, 410 ; 



of dogfish, 469 



Shoulder-girdle, see Pectoral arch 

 Sinus : blood-, 376, 377, 408, 457, 



lymph-, 1 8, 27 ; urinary and 



urinogenital, 467 ; venosus, 80, 



89, 449, 520 



Siphon, inhalant and exhalant, 397 

 Skeleton, see Endo- and Exo- 



skeleton 



Skin, see Integument 

 Skull; Frog, 16, 35, 39; Dogfish, 



436 ; Rabbit, 487 ; development 



of. 595 



Smell, organ of, see Olfactory organ 

 Snout, 4 



Somatic layer of mesoderm, 579 

 Somatopleure, 579 

 Spawn, 9 

 Species, 215 et seq. ; origin of, 222, 



225 

 Sperm, or spermatozooid, 194, 382, 



566 ; and see under various types 

 Spermary, 25, 193, 194 ; and see 



Reproductive organs 

 Spermatogenesis, 194, 565 

 Spermatophore, 382 

 Spermiduct, 193, 347, 382, 467, 



538, 594 



Spermotheca, 347 



Sperm-reservoir, 347 



Sperm-sac, 347, 467 



SPH^RELLA : general characters, 

 240 ; rate of progression, 240 ; 

 ciliary movements, 242, 250 ; 

 colouring matter, 242 ; motile 

 and stationary phases, 244 ; nu- 

 trition, 245 ; source of energy, 

 248 ; dimorphism, 250 ; repro- 

 duction, 250 ; conjugation, 251 ; 

 animal or plant ? 255 ; . practical 

 directions, 259 



Sphincter, 71 



Spinal cord, 28, 155, 424, 459, 532 



Spiracle, 432, 449 



Spiral valve, 445, 515 



Splanchnic layer of mesoderm, 579 



Splanchnopleure, 579 



Spleen, 23, 98, 447, 516 



Spontaneous generation, see Abio- 



genesis 



Spores, 254, 275, 285 

 Sporozoa, 284, 292 

 Sporozoite, 286 

 Stalk of Vorticella, 269, 272 

 Stapes, 46, 189, 492, 536 

 Starch, 72, 243 

 Statocyst, 315, 381, 409 

 Sterilised infusions, 289 

 Sternal canal, 363 

 Sternebrse, 500 



Sternum, 16, 48, 361, 486, 500 

 Stimulus, various kinds of, 62 

 Stock, see Colony 

 Stomach, 22, 70,401, 445, 512 

 StomodiEum, 204, 384, 445, 447 

 Struggle for existence, 226 

 Submucosa, 130 

 Substitution of organs, 209 

 Sucker, 203 

 Supination, 501 



Supporting lamella, see Mesoglcea 

 Suprarenals, 447 ; and see Adrenals 

 Suspensorum, 40, 438 

 Sutures, 50, 487 

 Swimmeret, see Pleopod 

 Symbiosis, 304 

 Sympathetic, see Nerves 

 Symphysis, 503 

 Syn-cerebrum, 380 

 Synovial capsule, 56 

 Systemic arch, 80, 452, 523 

 Systole : of heart, 90 ; of contractile 



vacuole, 266 



1 actile organs, 179, 353, 382, 533 

 Tadpole, 9, 203 et seq. 

 Tail, 9, 209, 432, 483 

 Tapetum, 356 

 Tarsus, 51, 504 

 Taste-organs, 180, 534 



