A Monograph of the British Graptolitidae

A Monograph of the British Graptolitidae

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1872 edition. Excerpt: ... process is tapering and trian-A. Difilvgrflrw centsvm@1centsG@i"'. en.." larged. B, D.acuminatus, Nich., gular in shape, and ends proximally en1a, ged. (O, ig, na1.) in a blunt extremity, which is sometimes slightly bulbous, and which does not appear ever to Fig. 27. A B exhibit any extension of the solid axis alone. The nature of the rounded, and sometimes truncated, base in these forms is such as to show plainly that the organism could not have been attachedat this point. In the genus Cli1nacograp.'us, Hall, comprising forms nearly allied to the Dzplograpsi, the exact nature of the base varies very much, even within the limits of the same species. In the commonest and best known species--viz., C. teretlusoulus, His.--there appears to be normally a single basal process or "radicle," composed of a longer or shorter proximal exten: z, Base of the common form of Climncograpsur teretiusculus, with a short radicle: Coniston Mudstones. 13, Base of the same, showing a long median radicle and two long lateral spines: Upper Llandeilo, Dobb's Linn, near Moffat. o, Base of the same, showing the commencement of the radicle enveloped in a sheath: Upper Llandeilo, Hart Fell, near Moffat. ii, Base of the same, showing the radicle swelling out below into a species of vesicular dilatation: Upper Llandeilo, Garple Linn, near Moffat. All much enlarged. (Original.) sion of the solid axis alone (see fig. 8, a and b, and fig. 28, a). In some cases this process is very short, but in others it attains an extraordinary length. In some other forms of the same species, as originally pointed out by Mr Carruthers, the commencement of this radicular extension of the axis is enveloped in a kind of sheath derived from the polyparyshow more

Product details

  • Paperback | 42 pages
  • 189 x 246 x 2mm | 95g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236943937
  • 9781236943934