ON DIPLOGRAPTIDiE, Lapworth.^ 



In the fall of 1888, H. Munthe brought from Bornholm a 

 piece of Baltic sea limestone^ [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 frag- 

 ments, which consist mainly of proximal-ends and sciculae, fur- 

 nish excellent material for the examination of the inner organi- 

 zation of this particular Diplograptus. 



These remains are of a half-carbonized, chitinous substance, 

 and after separation were dark brown and almost opaque, there- 

 fore I treated them with Schulze's maceration medium by which 

 their color was changed to light brown or yellow. After care- 

 ful 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 Diplograptidce, 

 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. 



'Extract from Bulletin of the Geological Institute of Upsala, Vol. I, No. 2, 1893. 

 Translated from the German by Charles Schuchert. 



= C. WiMAN : Ueber das Silurgebiet des Bottnischen Meeres, I, p. 73, Bull. Geol. 

 Instit., of Upsala, Vol. I, No. i, 1893. 



3K. A. ZiTTEL : Handbuch der Palseontologie, Abtheilung I, Band I, 1876- 1880. 

 H. A. Nicholson and R. Lydekker : A Manual of Palaeontology 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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