To J. E. Gray 1 July 1
Down Bromley Kent
My dear Gray
You once told me that you would help me in my Essay on variation. I want much some information on a point of Geographical Distrib., & to be allowed, to give information on your authority. It is, whether there are genera of Echinoderms, starfish &c, which have species (especially if closely related) in the Northern & Southern seas, but have not any one species in the Tropical seas? Or whether there are any closely related & representative genera in the north & south, without any closely related genus within the Tropics?2
I am quite ignorant about the range of Echinoderms & perhaps all the genera have very confined ranges. Could I find information on this head in any publication?
Pray forgive, if you can, the trouble, & believe me, Yours very sincerely | Ch. Darwin
Requests information on ranges of echinoderms for his essay on variation [Natural selection]. Are there genera with representative species in northern and southern seas, but none in tropics?
Please cite as
Darwin Correspondence Project, “Letter no. 1915,” accessed on 23 April 2017, http://www.darwinproject.ac.uk/DCP-LETT-1915