Claus, C. (1880). Grundzüge der Zoologie, zum wissenschaftlichen gebrauche [fourth edition]. [Principles of Zoology, for scientific use [fourth edition]]. N.G. Elwert'sche Verlagsbuchhandlung, Marburg. 1: 1-822. [Copepoda :543-560].
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Claus, C.
1880
Grundzüge der Zoologie, zum wissenschaftlichen gebrauche [fourth edition]. [Principles of Zoology, for scientific use [fourth edition]]
"Principles of zoology, for scientific use" Record for Volume 1 only. BHL DOI for both volumes = http://dx.doi.org/10.5962/bhl.title.1113 Cnidaria = p.222-294. Annelida = p.455-505