Asks whether the blind cave animals described by B. Silliman Jr [Am. J. Sci. 2d ser. 11 (1851): 332–9] belong to genera found only on the American continent.

On geographical distribution of Crustacea, CD asks whether northern genera sent species to the Southern Hemisphere or did southern genera send species north?

Does he know of any author who has described fossil trees in South Shetland Islands?

Responds to CD’s query about the blind fauna of Mammoth Cave.

Gives information from L. Agassiz. Distribution of Crustacea, especially along southern coastlines.

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.

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".

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.