Sends a paper on reproductive modes of Leptodera ["Organisation und Fortpflanzen von Leptodera", Schr. Ges. Beförd. Naturw. Marburg (1869)].

Criticises Ernst Haeckel’s work as too unripe and enthusiastic.

Asks CD for some specimens of cirripedes in pupal stage for a work in progress.

Thanks CC for two memoirs [see 6575. The other was possibly "Die Cypris-ähnliche Larve der Cirripedien", Schr. Ges. Beförd Naturw. Marburg (1869)].

Haeckel is too enthusiastic and too bold in drawing conclusions.

CD sees no reason to add to what he says on isolation, in new edition of Origin.

Lists specimens he has available for CC’s intended study of metamorphoses of Lepas.

Pleased by CD’s good opinion and offer to provide material. Discusses work he would do on cirripedes.

Moritz Wagner’s views on migration of species;

his doubts about Fritz Müller’s views on developmental stages of Crustacea.

The cirripede material mentioned in CD’s letter of 10 Feb has not arrived. [Asks CD to inquire of Williams and Norgate, who forwarded it.]

Williams and Norgate inform CD that they dispatched the small parcel to Leipzig on 23 February. CD fears it may not be worth the trouble to CC.