INDEX 



G35 



Segmentation, equal and un- 

 equal, 575 ; dis- 

 coid, 575 

 ,, superficial, 383, 



575 

 metameric, see 



Metamere 



,, -nucleus, 572 



Selection, natural and artificial, 



226, 227 



Self-fertilisation, 348 

 Seminal funnel, 347 



vesicle, 194, 347, 467 

 Sense-organs and cells, 179, 315, 



344> 351, 380, 409, 424, 432, 



464. 533, 592 

 Septa, of earthworm, 333 

 Septum : lucidurn, 531 ; nasal, 



42, 493 ; interorbital, 487 

 Serous membrane of embryo, 



609, 610 



Sesamoid bones, 502, 505 

 Seta, 328, 350, 351, 362 

 Sex-cells, primitive, 566, 568 

 Sexual characters, external, 7, 



382, 433, 486 

 Sexual generation, see Gamo- 



bium 

 Sexual organs, see Reproductive 



organs 

 Sexual reproduction, see under 



various types 

 Shank, 5 



Shell, 396 ; larval, 410 

 Shell of egg, 470, 566 

 Shell-gland of mussel-embryo, 



410 ; of dogfish, 469 

 Shoulder-girdle, see Pectoral 



arch 

 Sinus : blood-, 376, 377, 408, 



457; lymph-, 18, 27; urinary 



and urinogenital, 466, 



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 ; develop- 

 ment of, 604 



Smell, organ of, see Olfactory 

 organ 



Snout, 4 



Somatic layer of mesoderm, 580 



Somatopleure, 580 



Spawn, 9 



Species, 215 et seq. ; origin of, 

 222, 225 



Sperm, or Spermatozooid, 194, 

 382, 568 ; and see under 

 various types 



Spermary, 25, 193, 194 ; and see 

 Reproductive organs 



Spermatic substance, 9 



Spermatogenesis, 194, 566 



Spermatophore, 382 



Spermiduct, 193, 347, 382, 466, 

 53 8 - 603 



Spermotheca, 347 



Sperm-reservoir, 347 



Sperm-sac, 347, 467 



SPH^ERELLA : general characters, 

 240 ; rate of progression, 240 ; 

 ciliary movements, 242, 250 ; 

 colouring matter, 242 ; motile 

 and stationary phases, 244 ; 

 nutrition, 245 ; source of 

 energy, 248 ; dimorphism, 

 250 ; reproduction, 250 ; con- 

 jugation, 251 ; animal or 

 plant ? 255 ; practical direc- 

 tions, 259 



Sphincter, 71 



Spinal cord, 27, 155, 424, 459, 

 532, 592 



Spindle, nuclear, 560 



Spiracle, 432, 449 



Spiral valve, 445, 515 



Spireme, 560 



Splanchnic layer of mesoderm, 

 580 



Splanchnopleure, 580 



Spleen, 23, 98, 447, 516 



Spontaneous generation, see 

 Abiogenesis 



Spores, 254, 275, 286 



Sporozoa, 284, 292 



Sporozoite, 287 



