brown ; they have not the red eyelids, nor the horny plates above and below the eye, nor have they the puckered yellow skin at the base of the bill, and what is still more remarkable, the bill is differently formed ; it is neither of the same size, shape, nor colour, and the pieces of which it is composed are not even the same. It is small, sliced off (tronqué) in front, especially at the lower man- dible, wanting the pleat (ourlet) at the base, and flattened laterally on a level with the nostrils, where a solid horny skin of a bright lead-colour is replaced by a soft greyish membrane.
" Hitherto authors have considered the Puffins found in this state to be the young, of different ages, of Mormon arctica.* This view was even generally adopted, when M. J. Vian, examining a large number of specimens procured in winter on the coasts' of Fiance, and recognizing amongst them both old and young, thought that they should be specifically separated from Mormon arctica under the name Mormon grabæ.f
"Neither of these views can be admitted. The first falls to the ground before the facts which I am about to detail ; as to the second, in order to end all doubt, my friend M. Vian, admitting that, in view of my recent observations, Mormon grabæ has no longer any claim to specific distinction, has made a point of assisting me by obligingly placing at my disposal the specimens which served him as types. Dr. Marmottan, too, whose ornitho- logical collection is rich in material for a study of the fauna of France, has entrusted me with his fine series of Puffins. A large number of specimens, from all quarters, have in fact been offered to me. I shall use them later, when, after another season's observations on the coast of Brittany, 1 shall make known some other interesting points in the history of the Puffin. For the present I shall confine myself to a study of the metamorphoses to which the beak and the palpebral appendages of these birds are subject after the breeding season.
"It will perhaps be interesting to state here the different stages of enquiry through which I arrived at the discovery of the meta- morphosis in question. I had for some years remarked that the beak of specimens killed on the French coast belonged to two very
See 'The Zoologist' for 1862, pp. 8003–4 and 1863, p. 8331.
t Bull. de la Soc. Zool. de France, 1876, p. 4. M. de Norguet (Bull. Scient. du Dep. du Nord, 1877, p. 39) sees in Mormon grabæ merely individual varieties of Mormon arctica.
