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V.—On the Graptolite Family Dichograptidæ, Lapw

Published online by Cambridge University Press:  01 May 2009

Extract

Hydrosoma bilaterally developed. Branches regular, always furnished only with a single series of hydrothecæ (Monoprionidian). Hydrothecæ rectangular, touching one another, their inferior margin slightly curved. Sicula generally persistent; its free, pointed, downwardly directed end at the proximal extremity of the hydrosoma.

In 1851 M Coy (Brit. Pal. Foss. p. 9) proposed the generic name Didymograptus for two-branched species with one row of cells “sometimes on the inner, sometimes on the outer side of the branches.” Nearly at the same time Geinitz established his genus Cladograptus to include all two-armed or furcate Graptolites.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1886

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References

page 13 note 2 Introduction to the Study of the Graptolites, Albany, 1868, p. 234.

page 13 note 3 Geol. Mao. 1871, Vol. VIII. p. 20, Pl. I.

page 18 note 1 Phyllograptus-shales, Norway.

page 18 note 2 See Notes on British Graptolithes, by C. Lapworth, F.G.S., GEOL. MAG. 1873,