Dear Lubbock

I have written to Hooker to enquire. The case has been described in Linn: Transactions.—² Many of Spallanzanis experiments seemed to show that plants have been produced without pollen;³ but the subject has been discussed backwards & forwards of late years,—& largely by Gærtner in his Beitrage zur Kenntniss &c.⁴ But I cannot possibly spare this Book for about a fortnight. for I am using it daily.⁵

I think your explanation of the inner saddle perfectly satisfactory; it is in fact Continuous with inner membrane of carapace, like the outer saddle is with the outer membrane of carapace.—

But I demur vehemently to your calling the under membrane of carapace “Corium”⁶ The “corium”, I apprehend, w^d be represented by the dotted line between these two membranes, & at each moult, would form a new upper & a new under membrane. Corium or true skin will never, I imagine, be freely exposed to water or air; its very nature, I apprehend, is to be covered with epidermis or chitine membrane, which it generates at each fresh moult.—

Your’s very sincerely | C. Darwin

No doubt the corium itself is double or a fold

Would not longitudinal section of posterior end, together with tranverse section make things clearer?.—⁷

This would show how both inner & outer saddle were moulted together. You could give true outline longitudinally of carapace.