RECORD: Darwin, C. R. 'Prof. Forbes says he thinks that all Gasteropods pass through state of almost of Ascidian molluscans' (3.1844) CUL-DAR205.9.185-187 Transcribed by Kees Rookmaaker (Darwin Online,

REVISION HISTORY: Transcribed by Kees Rookmaaker, corrections by John van Wyhe 11.2010. RN1

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March 20. —. 44.

Prof. Forbes says he thinks that all Gasteropods pass through state of almost of Ascidian molluscans, like

N.B. [illeg] one of the oldest molluscans. Suspect same with Cephalopods.

Says he has no dount in many cases of relation of extinct & living sea-shells, like Australian case of mammals. — Says there is case like the Galapagos, in land Mollusca of different islds of Graecian archipelago, having their own species. — There are fossil Tertiary shells of heights of many thousand feet on Mount Taurus. — Flora of Mt. Taurus very peculiar. — The young of all Gasteropods, when free from envelope of nidus, swim freely, hence dispersal. — Most wonderful, in one uniform bed ?/ thickness & whether spaces full of shells? with a Melania & some other shells, I think 3 species, all with a smooth


outside, then in middle of the bed all with rougher outside & then at top all with very protuberant roughness. — Most wonderful — On common Creationist view, one must look at this roughness as some relation or effect, & like the colouring of insects in the Phillippines, shows the external influences do produce some marked effects. — There is no gradation between their forms — but if there had been a gradual change, & there sets suddenly seized & preserved, effect would be this — Grand case

Forbes tells me bed stratified & I think of same materials full of shells, some parts fuller than others, cannot say that a hair-line divided the three sets, but is sure of main fact.


March 20 /44/

Falconer again insisted on antiquity of Testudo tecta as argument against mutability! yet admits that all even genera, are mere chasms, & calls that the real philosophy. —

He has wonderful fossils, with these a pig, with teeth wonderfully approaching a horse — Pachydermata with teeth wonderfully approaching a Ruminant, & seems to admit, that as far as these characters go our present groups get more & more broken down. — A Racehorse horse

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Citation: John van Wyhe, editor. 2002-. The Complete Work of Charles Darwin Online. (

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