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.

    946/1074 (page 926)
    Germs BERKELETA (Grev.). — Frustules naviculoid, linear-lanceolate, included within tubtdar snbmembranaceous filaments, which are free at their extremities, but immersed below in a more or less definite tubercle. Marine Berkcleya differs from Schizonema in having the base ot the la- ments immersed in an orbicular gelatinous tubercle. This tubercle is at first firm and definite, but finally, especiaUy when growing on rocks, becomes enlarged, soft, and often somewhat indefinite Bebkeleya fragilis (Grev.). — Fila- ments subsimple, minute; frustules crowded, slender, lanceolate or linear- lanceolate, with the strise obsolete or wanting. GBF. p. 416; SD. ii. p. 67, pi. 54. f. 344. On Zostera, Algae, and rocks. Eiu-ope. The gelatinous tubercle duiing growth becomes attenuated and more diifiised, and sometimes forms an indefinite slimy covering about the base of the filaments. In a dried state this species acquires a metallic lustre. B. Adriatica (K.).—Filaments branch- ed ; branches distinctly subdivided; frus- tules narrowly linear-lanceolate, rather obtuse. KB. p. 109, pi. 22. f. 4. Adriatic Sea. (XIV. 34,35.) 1-300. Scarcely distinct from B. fragilis. ^ ' J Genus COLLETONEMA (Breb.).—Frustules naviculoid, arranged iii series within a tender, simple or divided, filiform or globose frond Aquatic recording to Professo^ Smith, the freshwater habitat and shghtly divided frond distinguish the present genus from Schizonema; and [he adds] the Sustulfs arf also more firmly siHceous than those of that ge-s, and the character of the valve can usuaUy be well seen after maceration m acid. Profe 0 ■ Mug describes Colletonema as having a filiform frond composed of serie of navic^^ held together and enveloped by an amoiT^hous gelatoous mucus, without an exterior gelatinous tube. We doubt if any of the above Xracters sufficiently distinguish CoUetonema from the allied genera beca^^e ?hey a e either inadmissible in generic definit ons, uncertain, or no pecidiar to the genus. The absence of an external tube, if constant, would be of oenericrportance ; but we sometimes find the fi^stiile contamed withm an Sent (although t;nder and evanescent) tube, whilst in Micromega on the oSer hand, the presence of an external tube is sometimes doubtful The ?ronds ie excee^gly thin and tender, readily permitting the escape of their SlTwSTay then be mistaken for species belonging to other genera; tSisMeTsoi Smith remarks that it is possible that F^nnular^a rachosa may le mSy the free state of CoUetonema neglectum, and Nav^cula crass^nerv^a the same condition of C. vulgare. Colletonema eximium (Thw., K.). — Frond filiform; frustule in lateral view sigmoid, stiiated. KA. p. 891; SD ii. p. 69, pi. 56. i. 350. = Schizonema eximium, ANH. 1848; Gloionema sig- moides, EB. 1845; Encyonema sigmoides, KA. p. 62. ? Britain, Demerara ? Valves linear, sigmoid from the ends sloping m opposite directions; striss 56 in -001. ^'^c'vSdulum (Br6b.).—Frond filifoi-m; naviculiB spirally and densely an-anged; valves lanceolate, rather obtiise, smooth; front view hnear-oblong, slightly and gradually attenuated towards the trun- cate apices. KA. p. 105. France 0. Lustre (Ag., K.).-Frond filiform, simple or subramose, finer than a haii, enclosed in an imperceptible membrane; naviculfB elliptic or parallelogramic, m a single or double series. KbA. p. luo. = Schizonema laat-stre, Ag CD. p. 18. Sweden. Tufts erect, brownish yeUow; m size and habit like Sphacelaria cuTosa. C. vidgare (Thw.). — Frond falifomi, simple or divided, graduaUy tapermg, containing one or two regular rows ot frustides; valves oblong-lanceolate, witli shs-htly contracted, obtuse ends, b U. u. p 70 pi. 56. f. Q51. = Schizone7}ia vulgare, ANH 1848. England and France. Less common, according to Profe.^or Smith, than the next species. Strife i 2 in -OOi . C. neqkctum (Thw.).-Fi-oud shghtly divided, obtuse, containing numerons and closely packed frustules; valves lan- ceolate, witli obtuse ends. bJiiJ. u- V 70, pi. 56. f. 352. = Schizo?iema neg- lectum, ANU. 1848. England. C. stcbcoharens (Thw.).--Frond glo- bose, gelatinous, pervaded by -reguiar rows of frustules; valves oblong, with