My dear Lyell

I return the Whewell correspondence² with thanks: I do not know whether you thought any answer of Whewell’s was enclosed with your’s; such certainly was not the case.— I like your letter very much, & admire your cool boldness. The Master of Trinity must have been surprised at being argued with on terms of such perfect equality; & if he thought you meant to publish it, I am not the least surprised at his calls & civilities to avoid anything so unpleasant.

I, also, return Silliman³ & am glad to have seen D^r. Morton’s arcticle:⁴ my opinion, of it, as you ask for it, is that it is in main part, a merely tabulated compilation from Griffith’s Cuvier,⁵ with a few other facts interpolated. He is, I think, too credulous; but it is a pretty good compilation: his worse fault is that he has not gone to his original source,—thus he makes a great flourish about perfect fertility of the genus Crax:⁶ whereas the original authority, namely Temminck says speaking of these hybrids, “a great number are quite sterile, others have bred once, & a smaller number have produced a good many young,”⁷ & it is not stated that the crosses have been inter-se; on the other hand between two other species of Crax it is stated that the crosses were with either parent: no doubt by these crosses a multitude of hybrids have been produced, but there is a want of exactness in the manner Morton gives the facts.— Again, he takes as his single instance of a bigeneric cross in plants, a case which has been tryed in vain in England & of which the accuracy has been publickly challenged.—⁸ In conclusion, therefore, I do not think D^r. Morton a safe man to quote from, without going to his authority; nor has he discovered any recondite authorities.

What a capital Journal Silliman’s is; there is always something of interest in it.

Farewell | Ever yours | C. Darwin

D^r. Morton quotes Temminck as authority for two wag-tails crossing in wild-state,⁹ in case you sh^d believe this from the high authority of Temminck, I may just add that the species have only quite lately been made out (if they now are) in Motacilla & that this very cross has been doubted by good authority.— He makes confusion about the crossing of crows, by supposing that the common crow C. corone!! is different from carrion crow & thus makes hybrids between 3 nominal species—whereas there is doubt about any on account of black varieties of the Royston Crow¹⁰ so I c^d go on, but will not waste your & my own time