Has reduced 20 Cyrena species to geographical varieties of one species, Cyrena fluminalis. Hooker is reducing Indian flora at the rate of 19 to 1.
Recommends W. H. Harvey’s Seaside book [1849] and Charles Pickering’s Races of man [1850].
Showing 61–80 of 125 items
Has reduced 20 Cyrena species to geographical varieties of one species, Cyrena fluminalis. Hooker is reducing Indian flora at the rate of 19 to 1.
Recommends W. H. Harvey’s Seaside book [1849] and Charles Pickering’s Races of man [1850].
Lists Lusitanian shells with wide ranges beyond that geographical province.
Antiquity and elevation of land mass is more important than latitude for the distribution of shells.
Responds to CD’s questions about the geographical distribution of freshwater fishes.
Thanks for information about variability in shells.
Comments on Harvey’s Seaside book [1849].
"I am growing as bad as the worst about species and hardly have a vestige of belief in the permanence of species left in me".
Multiple creations.
Necessity for crossing in plants and animals: JDH to take up the subject; explains separate sexes in trees.
Continental extensions.
CD’s predicament with continental extensions: they would remove argument for multiple creations, yet he opposes the doctrine. Lyell will not express an opinion on this.
Lyell fears mutability would lead to more specific names.
Encloses copy of letters to Lyell [1910 and 1917].
Believes intermediate varieties are generally less numerous in individuals than the two states that they connect.
Discusses the difficulties of deciding what is the typical form of a species
and gives some opinions on the variability of introduced species compared with indigenous species.
One plant in self-sown patch of Aegilops has assumed a triticoidal character; JSH feels it may be an example of Aegilops passing to wheat.
JDH’s arguments against transmutation: 1. Plants do not show the confusion he would expect; 2. Under clearly similar physical conditions we do not find same species.
JDH’s argument against migration: commonality of alpine species. Believes migration opposes facts of botanical distribution in Van Diemen’s Land and New Zealand; prefers continental extension theory.
Agrees that Lyell’s letters shed no new light on extensions issue. Continental extensions: opposes their being hypothesised all over world.
Commonality of alpine plants damns both extension and migration.
Reports on results of forcing and other attempts to produce variations in plants. Asks for some seeds.
Is correcting his Linnean Society paper ["On the action of sea-water", Collected papers 1: 264–71].
Antarctic plants most difficult to account for on any theory. Lyell’s iceberg transportal of seeds.
Are there more representative species of American origin in Tristan da Cunha than in Kerguelen land?
Tristan da Cunha flora.
Aquatic plants.
Density and diversity of plants in small plots in Kent, Keeling Islands, and Himalayas.
Quotes passage from [Frédéric?] Gerard on distribution of certain Lepidoptera.
Whether or not there should be movement of particles according to Tyndall’s theory of glacial action ["Observations on glaciers", Not. Proc. R. Inst. G. B. 2: 54–8, 441–3].
CD subscribes to H. C. Sorby’s view of gneiss [Edinburgh New Philos. J. 55 (1853): 137–50].
Seed-salting.
Pigeons.
Significant differences in skeletons of domesticated rabbits.
Reports on the naturalised animal life of Ascension.
C. T. Beke has communicated to the Mauritius Natural History Society a letter he received from CD. VdeR attempts to answer questions on transport of seeds by the ocean.
Plants that are social in the U. S. but are not so in the Old World.
Distribution of U. S. species common to Europe.
Gives Theodor Engelmann’s opinion on the relative variability of indigenous and introduced plants and notes the effects of man’s settlement on the numbers and distribution of indigenous plants.
Sends review by Quatrefages [de Bréau] of Owen’s Parthenogenesis [1849].
J. D. Dana’s congratulations on JL’s marriage.
Will send MS on one point of geographical distribution. It is "of infinite importance" that JDH see it, for CD has never felt such difficulty in deciding what to do.
Wants capsules of aquatic plants, to float in sea-water.