ii74 



INDEX 



SIL 



Silex in Equisetacece, 680 ; in epiderm of 



grasses, 715 



Silk glands of spiders, 1015 

 * Silk-weeds,' 569 

 Silkworm,' eggs of, 1005 , 

 Silkworm diseases, 645, 661 

 Silpha, antennae of, 988 

 Simple magnifier, 37 



microscope, 248 

 Sines, law of, 3 



Siphonacece, 562-564 ; Munier-Charles 



on fossil forms of, 564 

 Siphonostomata, 965 note 

 Siricidce, ovipositor of, 1003 

 Sirodot, on alternation of generations in 



Batracliospermum, 575 

 Skate, muscle fibre, 1049 

 Skeleton, dermal, of Vertebrata, 1026 ; 



fossilised, 1090 



fibrous, of sponges, 857 



silicious, of Heliozoa, 734 ; of Eadio- 

 laria, 846 



of sponges, 855; of zoophytes, 862; 

 of Echnoidea, 884; of Asteroidea, 

 891 ; of Ophiuroidea, 891 ; of Crinoidea, 

 892 ; of Holothurioidea, 894 ; of Ante- 

 don, 901 ; of Vertebrata, structure of, 

 1020 



Skin, 1041 ; pigment-cells in, 1042 ; capil- 

 laries in, 1062 

 Skip-jack, antennae of, 987 

 Slack, on the costse of Pinnularia, 617 

 Slack's optical illusion, 428 

 Slide-forceps, 453 

 Slides, glass for, 438 

 Slides for cultures, 340, 841 



Seiler's solution for cleansing, 439 

 Sliding-plate of objectives, 290 

 Sloths, fossil, teeth of, 1024 



Slug. See Limax 



Slug's eye, 941 



Slugs, Motif era in, 787 



Smell, organ of, in insects, 1000 



Smith's Cassegrainian microscope, 145, 

 146 



Smith (H. L.), on Tolles' binocular eye- 

 piece, 101 ; his vertical illuminator, 

 886 ; on classification of diatoms, 599 



Smith (James), his microscope, 155 ; on 

 use of bull's-eye with high powers, 

 881; his achromatic lenses, 356 ; his 

 separating lenses, 860 ; his mounting 

 instrument, 454 



Smith (T. F.), on markings of diatoms, 

 593 



Smith (W.), 011 cyclosis in Diatomacece, 

 587 ; on species of diatoms, 600 note ; 

 on habits of diatoms, 619 



Smith (W. H.), on structure of frustules, 

 590 note ; on movements of diatoms, 

 602 



Snail, 930 ; eye of, 941. See Helix 



muscle of odontophore, 1050 



Snake, lung of, 1063 



Snapdragon, seed of, 723 



Snell's ' Law of Sines,' 49 



Snow, crystals of, 1095 



SPH 



Suowberry, parenchyme of fruit of, 688 



Snowdrop, pollen-grains of, 722 



Soda, caustic, action on horny substances, 

 517 



Soemmering's simple camera, 278 



Sole, scales of, 1026, 1027, 1028 



Solen, prismatic layer in, 924 



Solid cones of light for minute observa- 

 tion, 419 



eye-pieces, 378 



image, 95 



- objects, delineation of, 88; correct 

 appreciation of, 88 



vision and oblique illumination, 61 

 Sollas, on sponges, 855 note ; on the ex- 

 tensions of the perivisceral cavity in 

 Polyzoa, 927 



Sorby (H. C.), on microscopic structure 



of crystals, 1066 

 Sorby' s parabolic reflector, 334 

 Sorby-Browning's micro-spectroscope, 



323 



Soredes of lichens, 649 

 Sori of ferns, 675 

 Sound-producing apparatus of crickets, 



999 



Spatangidium, 610 

 Spatangus, spines of, 889 

 ' Spawn ' of mushroom, 647 

 Spectacles, invention of, 118 

 Spectra, diffraction, 67 



artificial, 324 

 Spectral, ocular, Zeiss's, 827 

 Spectro-micrometer, bright-line, 325 

 Spectroscope in micro-chemical opera- 

 tions, 1103 



Spectroscopic test, 324 

 Spectrum, 19 ; irrationality of, 19 



binocular, microscope, 327 



map, 325 



natural, 824 



of dark lines, 323 ; of bright lines, 323 

 Speculum, parabolic, 333; Lieberkuhn's, 



334-336; in Smith's illuminator, 336 

 Spencer Lens Company's Microscopes, 



214, 215 - 

 Spermathecse of Gamasidce, 1012 ; of 



TyroglypMdce, 1012 



Spermatia oiPuccinia, 638 ; of lichens,650 

 Sperm-cells of Thallophytes, 536; of 



Volvox, 555 ; of ferns, 678 ; of sponges, 



857 ; of Hydra, 866 ; of Polyzoa, 907 

 Spermogones of Puccinia, 638 ; of 



lichens, 651 

 Sphacelaria, 626 

 Sphacele, 626 



Sphceria in caterpillars, 645 

 Sphceroplea annulina, 570-572 

 Sphcerozosma, rows of cells in, 583 

 Sphcerozoum ovodimare, 853 

 Sphagnacece, 673 

 Sphagnum, leaf of, 673 

 Sphenogyne speciosa, winged seed of, 724 

 Spherical aberration, 14, 15, 31, 299, 301, 



306, 387 

 diminished by Huyghens' objective, 



42 



