From Thomas Davidson 29 December 1856
Summary
His experience confirms CD’s view that some species and even some genera of Brachiopoda are consistently more variable than others, and that such variable forms are variable in all localities and at all periods. Similarly a species that shows a lack of variability does so at all points in time and space. Discusses the causes of variability. [See Natural selection, p. 106.]
Author: | Thomas Davidson |
Addressee: | Charles Robert Darwin |
Date: | 29 Dec 1856 |
Classmark: | DAR 162: 116 |
Letter no: | DCP-LETT-2024 |
From Thomas Davidson 3 May 1861
Summary
Sends three tables on the known geological distribution of genera and subgenera of Brachiopoda. Has been continually puzzled by intermediate forms, and is convinced that the greater number of species can be linked together. "Natura non facit saltum."
Author: | Thomas Davidson |
Addressee: | Charles Robert Darwin |
Date: | 3 May 1861 |
Classmark: | DAR 99: 1–2 |
Letter no: | DCP-LETT-3135 |
Darwin, C. R. | (2) |
Darwin, C. R. | (2) |
Davidson, Thomas | (2) |