Summary

Gratified by JDD’s opinion of his work.

Discusses problem of homologies of cirripede larva in first stage and reasons for his view.

JDD’s information on corals was just what CD needed.

Would like specimen of blind cave rat described by B. Silliman [Jr] ["On the Mammoth Cave of Kentucky", Am. J. Sci. 2d ser. 11 (1851): 336] for Waterhouse to examine.

Discusses origin of Australian valleys; he disagrees with JDD’s river-erosion hypothesis.

Summary

Agassiz has informed him that the mice and rats of Mammoth Cave are American in type.

Alludes to CD’s doubt of the principle that "progress of life on the globe is parallel with the development in different tribes". Outlines his own ideas on the "unfolding of the type-idea" and its "parallelism with the law of development in the embryo".

Summary

Thanks for sending paper on geological development (Dana 1856). Discusses infertility of species. Discusses first part of Asa Gray’s paper (A. Gray 1856–7). Thanks for note on the Cave Rat. Discusses a new species of fossil cirripede, in the genus Chthamalus. Explains his interest in pigeon breeding.

Summary

Thanks JDD for replies to queries [in 1925]; would like to know whether teeth of cave rat are of New or Old World type.

Wishes Louis Agassiz would publish his theory of parallels of geological and embryological development. "I wish to believe but have not seen nearly enough as yet to make me a disciple."

Is working hard on variations and origin of species, but fears it will be a couple of years before he publishes.

Describes his recent work on rabbits and pigeons.

The dispersal of land Mollusca is a most difficult problem.

Confesses he is sceptical of immutability of species; discusses difficulty of proving it.

Summary

Asks whether Crustacea from temperate parts of the Southern Hemisphere are more strongly analogous to those in same latitudes of the Northern Hemisphere than are Arctic to Antarctic Crustacea.

Discusses astonishing finds of mammalian and reptilian remains in Purbeck beds; notes reactions of Lyell.

Has doubts about Richard Owen’s recent classification of mammals [J. Proc. Linn. Soc. Lond. (Zool.) 2 (1858): 1–37].

Works away [on Natural selection].

Asa Gray has given valuable assistance.