History of infusoria, including the desmidiaceae and diatomaceae, British and foreign / by Andrew Pritchard.

  • Andrew Pritchard
Date:
1861
Catalogue details

Licence: Public Domain Mark

Credit: History of infusoria, including the desmidiaceae and diatomaceae, British and foreign / by Andrew Pritchard. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

    948/1074 (page 928)
    mine the genus, even before minute microscopic examination. We place more reliance upon colour in the discrimination of species than some writers allow The colour for the most part depends upon the contents of the fms- tules, and, according to our experience, is sulycct to httle variation except in old specimens rendered unfit for comparison by the escape of the navicuhe. * Central nodule transversely dilated. ScmzoNEMA ci-ucif/er (S.)-—FUaments much divided; naviculse crowded; valves lanceolate, acute, striated; me- dian nodule transversely dilated into a stauros. SD. ii. p. 74, pi. 56 f. 354. Britain. Striae distinct, 40 in -001 . 2 * Central nodule pimctiform, sometimes obsolete. S. Ch-evillii (Ag.).—Frond membra- naceous, much branched, level-topped; naviculte in fi'ont view sub(iuadrate; valves oblong-lanceolate, with 60 striap in -001. AgCD. p. 19; SD. ii. p. 77, pi. 58. f. 364. = Monnema GreviUn, Meneg.; S. quadripunctatum, Harv. On roclis and mud. Fronds densely tufted, brown, tm-ning to a dirty verdigns-gi'een when dried, and adhering unperfectly to paper. Naviculse large, crowded at base, m a single file near the extremities.^ >S. quadripunctatum of British writers is an old state, and tui-ns of a rusty colom- m drymg. 1-576 'S. crinoideum (Harv.). — Filaments very slender, achromatic, sparingly branched, denselv woven into a pale- green or brownish stratum; naviculse very mmute, disposed in an hi-egulM loose series. Harv. Manual, p. 214. tenellum, KB. p. Ill, pi- 23. f. 8 ; Mon- nema quadripunctatum, Meneg. Jiurope. Filaments exceedmgly slender, with long, simple, flexuose branches. Brown when recent, olive-green and glossy when dry. S. Dillwynii (Ag.). — Frond densely tufted, rich brown, very slender; navi- cidffi minute; valves lanceolate-acute, smooth. SD. ii. p. 77, pi. 58. f 366 = Monema Dillwynii, GCF. pi. 297. Kocks, mud, and Alg£e. Naviculss imper- fectly silicious, more or less crowded, especially near the extremities; fronds tuiTiing deep green on immersion m fresh water, and quickly acquirmg an oftensive smell; generally glossy when dried. 1-1000. ^ , S. miJ?;cfli«m(Harv.).-Fiwd capil- lary, densely tufted, much _ branched, cS'ed, and'entangled; -f^'^^ZJ^] minut;, irre^idarlv crowded ;vah:es lan- ceolate, rather obtuse. SD. u. P- 'o, pi. 59. f. 367. On mud in sheltered places. Tufts of a duller brown than 8. Dillwynii, gi-aduaUy turning in fresh water to a dark olive-green, not quicldy becoming offensive. Frustules in form and size similar to those of S. mtilatis. S. dubium (Harv.). — Resembles S. Dillwynii; but the long branches, naked below, are furnished towards their sum- mits with numerous cmied ramuh. Harv. Manual, p. 212. = -S. Dillwynii 0, KA. p. 101. Kocks, &c. Tufts imequal- topped; apices of ramidi acute; naviculse very minute and densely packed. virescens (Harv.). — Fronds very slender, densely tufted, tenacious, verv much branched fr-om the base; ramuh numerous, cmied, upper ones longest, swellmg towards the tips, which are dark-coloured and end m a sudden point; navicxdee minute. Harv. Manual, p. 212. North Devon. Tufts dense, brownish olive, not much altered in drying. Under the microscope it has much the appearance of S. DiUioynii; but the thickened, dark-coloured tips are remarkable S. rutilans (Trentepohl, A^.).—Densely tufted: filaments elongated, subsmiple, brownish and empty at ba^e, hyahne and filled with crowded Imear-oblong frustides at the apex; when dry, shmmg and reddish. Ag CD. p. 18; KB. p. 112, pi 23. f. 6. 1, 2. = Monnevm rutdans, Mene<^. It differs from S. Dillwynii by its more vamish-hke lusti-e, reddish colom- when dry, and finer and more simple filament (Ag.). S; Hoffmannii (Ag.). — Filaments tufted, subshnple, arachnoid, when dry shining with a reddish lustre; navicula small, smooth, crowded; valves lanceo- late. --- S. rutilans, var. Soffmamn, KB. pi 23 110; MommnaHoffmanm,lslme^. feurope, Aberdeen, (x. 207.) Professor Kiitzmg makes this fonn a vai-iety ot 5'. r^dilnns^, butMeueghini observes that they difl'er in external characters and m the dimensions and shape of the uavi- culfe. 1-1080 to l-960._ S. Balticum (E.).—Navicidne striated, slender, linear-lanceolate, in fr-out view truncate, in lateral view subacute, dense, crowded in the mtricatelv branched hla- mentR. E Inf p. 236, pi. 20. f. 15.