Variability of certain features within insect genera.
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Variability of certain features within insect genera.
Discusses arthropod structure and the nature of the corium.
Outlines the ranges of northern U. S. species common to Europe. Hopes to investigate the resemblances between the floras of the north-eastern U. S. and western Europe. Discusses routes by which alpine plants appear to have reached U. S.
JDH approves MS section on geographical distribution.
Never felt so shaky about species before.
His objections to some mechanisms of distribution that CD proposes.
No summary available.
Greatly interested in CD’s experiments with seeds in salt water [see "Action of sea-water on seeds", Collected papers 1: 264–73]. Believes CD exaggerates the force of the objection, against migration, that seeds tend to sink.
CD relieved by JDH’s positive response to his MS.
CD continues observations on means of transport.
JDH’s Raoul Island paper [J. Linn. Soc. Lond. (Bot.) 22 (1857): 133–41], showing continuity of vegetation with New Zealand, best evidence yet of continental extension.
Makes arrangements for Linnean Society meeting. Discusses local politics and ‘Memoranda’ written by JSH.
No summary available.
Describes the funeral of Aunt Sarah [Elizabeth Wedgwood].
Believes he can give CD information on Mammalia of St Thomas [São Tomé, Gulf of Guinea]. Quotes from a Portuguese history of the islands on unique species of monkeys and civet cats found there.
CD finds JDH’s objections to a mundane cold period significant, and he endeavours to show how they do not rule out mutability.
He is writing on crossing.
No summary available.
JDH not happy with CD’s explanation of the absence of north temperate forms in the Southern Hemisphere, given his explanation for the spread of sub-arctic forms to the south. [CD’s note is in response to JDH’s criticism.]
CD encloses letter from Asa Gray, although it is critical of JDH.
Role of struggle in forming species in retreat from advancing glaciers.
No summary available.
Discusses means of seed transport.
Considers the difficulty of deciding which, if any, botanical species are real.
He is not sure whether he has seen Subularia flowering above the water, but thinks it probably is an aerial flowerer, at least sometimes.
Has been unable to find an anonymous book on pigeons in the University Library.
Continued debate on formation of species as a result of retreat from glaciers.
JDH suggests internal powers of species modification, which he knows CD abhors.
CD, attempting to clarify debate, states more of his position. External conditions cause "mere variability". Formation of species due to selection. Relation of an organism to its associates far more important than external conditions.