ii74 



INDEX 



SIL 



Silex in JSquisetacecB, 680 ; inepiderm of 



grasses, 715 



Silk glands of spiders, 1015 

 ' Silk-weeds,' 569 

 ' Silkworm,' eggs of, 1005 

 Silkworm diseases, 045, 661 

 Silplia, antennae of, 988 

 Simple magnifier, 37 



microscope, 248 

 Sines, law of, 3 



SiphonacecE, 562-564 ; Munier-Charles 



011 fossil forms of, 564 

 Siphonostomata, 965 note 

 SiricidcF, ovipositor of, 1003 

 Sirodot, on alternation of generations in 



Batrachospermum, 575 

 Skate, muscle fibre, 1049 

 Skeleton, dermal, of Vertebrata, 1026 ; 



fossilised, 1090 



- fibrous, of sponges, 857 



silicious, of Heliozoa, 734 ; of Radio- 

 laria, 846 



of sponges, 855 ; of zoophytes, 862 ; 

 of EcJmoidea, 884; of Asteroiilrn, 

 891; of Ophiuroidea^Qlioi Crinoi</<'n, 

 892; of Holotlntrioiilea,894.; of Aiitc- 

 don, 901 ; of Vertebrata, structure of, 

 1020 



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

 laries in, 1062 

 Skip- jack, antenme of, 987 

 Slack, on the costas of Phunilnria, 617 

 Slack's optical illusion, 428 

 Slide-forceps, 453 

 Slides, glass for, 438 

 Slides for cultures, 340, 341 



- Seiler's solution for cleansing, 439 

 Sliding-plate of objectives, 290 

 Sloths, fossil, teeth of, 1024 



Slug. See Umax 



Slug's eye, 941 



Slugs, Eotifera in, 7*7 



Smell, organ of, in insects, 1000 



Smith's Cassegrainian microscope, 145, 

 146 



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

 piece, 101 ; his vertical illuminator, 

 336; on classification of diatoms, .V.rj 



Smith (James), his microscope, 155 ; on 

 use of bull's-eye witk high powers, 

 331 ; his achromatic lenses, 356 ; his 

 separating lenses, 360 ; his mounting 

 instrument, 454 



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

 593 



Smith (W.), on cyclosis in Diatomacece, 

 587; 011 species of diatoms, 600 >inlr\ 

 on habits of diatoms, 619 



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

 590 note; on movements of diatom-,, 

 602 



Snuil, 930; eye of, 941. See Hrli.r 

 - muscle of odontophore, 1050 



Snake, lung of, KM;:; 



Snapdragon, seed of, 723 



Snell's ' Law of Sines,' 49 



Snow, crystals of, 1095 



SPH 



Suowberry, pareiichyme of fruit of, 688 



Snowdrop, pollen-grains of, 722 



Soda, caustic, action on horny substances, 

 517 



Soemmeriiig'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 

 Poltjzoa, 927 



Sorby (H. C.), on microscopic structure 



of crystals, 1066 

 Sorby's parabolic reflector, 334 

 Sorby-Browiiiiig'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, 327 

 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, 324 



of dark lines, 323 ; of bright lines, 323 

 Speculum, parabolic, 333 ; Lieberkuhii's, 



334-336; in Smith's illuminator, 336 

 Spencer Lens Company's Microscopes, 



214, 215 

 Spermathecas of Gamasidce, 1012 ; of 



Tyroglypliidce, 1012 



Spermatia of Puccini a, 638 ; of lichens,650 

 Sperm-cells of TJiallophi/tes, 536; of 



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



857; of U //ih;i, soo; of Polyzoa,()01 

 S|ii'niiogoni>s of Puccinia, 638 ; of 



lichens, 651 

 Sphacelaria, 626 



, (126 



in caterpillars, 645 



annitUiia, 570-572 

 ,S'////,/ t;>-:osma, rows of cells in, 583 

 Sph&rozoum <>r<i<iiniare, 853 

 Sphagnacets, 073 

 K/I/HII/IIIIIII, leaf of, 673 

 Hji/n-noffi/iie fijii'ciiimi, winged seed of, 724 

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

 306, :;s7 



diminished by Huyghens' objective, 

 42 



