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On Diplograptidæ, Lapworth.[1]

In the fall of 1888, H. Munthe brought from Bornholm a piece of Baltic sea limestone[2] [Ostseekalk] with graptolites, which he kindly gave me, as I was at work on the Silurian region of the Bothnian sea. From this piece, half the size of one's fist, I have obtained, by the aid of muriatic acid and vinegar, several hundred pieces of a Diplograptus. As this compact limestone is excellently qualified to preserve the very finest details, the fragments, which consist mainly of proximal-ends and sciculæ, furnish excellent material for the examination of the inner organization of this particular Diplograptus.

These remains are of a half-carbonized, chitinous substance, and after separation were dark brown and almost opaque, therefore I treated them with Schulze's maceration medium by which their color was changed to light brown or yellow. After careful washing with water, they were further treated with alcohol and oil of cloves, and were then preserved in the ordinary way in Canada balsam.

According to the present acceptation, as recorded in general hand-books of paleontology,[3] and in the main the same as that given by Lapworth[4] as early as 1873, the family Diplograptidæ, Lapw., is characterized as follows: Hydrozoma, consisting of two branches united dorsally, between which the scicula is imbedded, its broadest portion forming the proximal end of the hydrozoma.

  1. ↑ Extract from Bulletin of the Geological Institute of Upsala, Vol. I, No. 2, 1893. Translated from the German by Charles Schuchert.
  2. ↑ C. Wiman: Ueber das Silurgebiet des Bottnischen Meeres, I, p. 73, Bull. Geol. Instit., of Upsala, Vol. I, No. 1, 1893.
  3. ↑ K. A. Zittel: Handbuch der Palæontologie, Abtheilung I, Band I, 1876-1880.H. A. Nicholson and R. Lydekker: A Manual of Palæontology for the use of students, Part I, Third Edition, 1889.
  4. ↑ Notes on British Graptolites and their Allies, I.—On an improved Classification of the Rhabdopora, Parts I and II, Geol. Mag., Vol. X, pp. 500, 555, 1873.

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