My dear M^r Darwin,

I send you tomorrow the Prion addressed to Orpington Station. I hope it will reach you all right.—¹ As the specimen is in spirit it will probably be sufficiently relaxed to enable you to examine the beak to your satisfaction but should this not be the case, pray treat it in any way that will render it so. All I wish is that the specimen should be of use.—

I see that the beak of the Flamingo is very duck-like as regards its lamellæ & it is possible though I have not had an opportunity of examining the point that these lamellæ may be adapted to the inverted position in which the bird feeds.—

There are numerous instances of a tooth-like formation along the edge of the bill-sheath of both upper & lower jaw in birds which are, perhaps, outside your present enquiries, still I can do no harm in directing you to Momotus Todus, Plotus, Buceros, Phytotoma, Ramphastos, some members of Euphonia Harpagus and the true Falcons.² in case you should require to examine them.—

I should think your suggestion that the lower series of lamellæ serve to clean the upper is very probably correct. In Prion, however, we find very delicate lamellæ on the maxilla but none on the mandible. This may arise from the difference of the water these birds feed in, from what ducks dabble in; And that no cleansing is necessary. The tongue too of Prion is curious.

Very truly yrs | Osbert Salvin.