. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. species o/" Didymograpsus. 341 ments,' at p. 563 (fig. 656), and by some oversight named ]). geminus, Ilis., is also really D. patidus. Log. Skiddaw Slates of Outerside, near Keswick, and Egg- beck, near Pooley; Lower Llandeilo, west of the Stipcrstones. (Also in the Lower Graptolite schists of Sweden, and the Quebec group of Canada.) Didymograpsus V-fractus, Salt. (Quart. Journ. Geol. Soc. vol. xix. p. 137, fig. 13 e.) This species, of which I subjoin a cut taken from Mr
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. species o/" Didymograpsus. 341 ments,' at p. 563 (fig. 656), and by some oversight named ]). geminus, Ilis., is also really D. patidus. Log. Skiddaw Slates of Outerside, near Keswick, and Egg- beck, near Pooley; Lower Llandeilo, west of the Stipcrstones. (Also in the Lower Graptolite schists of Sweden, and the Quebec group of Canada.) Didymograpsus V-fractus, Salt. (Quart. Journ. Geol. Soc. vol. xix. p. 137, fig. 13 e.) This species, of which I subjoin a cut taken from Mr. Salter's figure, was originally named by Mr. Salter from a specimen obtained from the Skiddaw Slates. Mr. Salter, however, never gave any description of the species, so that, unfortu- nately, it is hardly possible at present to decide positively as to its value. My own collection includes a few fragments, but no perfect specimen. The character upon which the spe- Fiof. Didymograpsus V-fractus, after Salter. Skiddaw Slates. cies was founded is the peculiar curvature of the stipes, which are bent abruptly outwards at the distance of about a quarter of an inch from the radicle. The fragments in my possession exhibit this character, but in all other respects they are abso- lutely undistinguishable from D. p)(ituliis, Hall. I should therefore be disposed to think that the form cannot be regarded as more than a variety of D. patuhis, unless this character can be shown to be constant in a considerable number of ex- amples. Loc. Barff, near Keswick (Skiddaw Slates). Didymograpsus extensuSj Hall, sp. PI. VIL figs. 2, 2 a. GraptoUtkus extensus, Hall (Grapt. Quebec Group, p. 80, pi. 2. figs. 11-lG). Frond composed of two long slender stipes diverging at an angle of 180° from a small radicle. The stipes attain a length of several inches without showing any signs of a termination. They have a breadth of about one-fiftieth of an inch close to the radicle, and not more than one-fifteen
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