238 THE ZOOLOGIST. 
“Tt is now ten years since my friend M. Marmottan recollects 
having killed, in September, 1867, in the Baie de Somme, a Puffin, 
from the beak of which several pieces were becoming spontaneously 
detached. 
“ The best way of obtaining a comprehensive idea of the changes 
which the beak and the palpebral appendages of the Puffin undergo 
after the breeding season is undoubtedly to cast a glance at the 
movable pieces figured on the accompanying Plate; but the pheno- 
menon is complex, and thoroughly to understand its different 
phases one must first comprehend the constitution of these parts 
in the adult in spring and in winter. 
“The adult Fratercula arctica in spring has the beak elevated 
at the base, the lower mandible regularly curved from the base to 
the extremity. The beak is divided into two very distinct parts ; 
one, the posterior, undergoes the phenomenon of moulting; the 
other, the anterior, remains unaffected :— 
“J, The posterior portion is formed by the combination and 
suture of nine horny pieces, which disunite and fall apart after the 
breeding season. ‘These are: on the upper mandible (fig. 1), the horny 
pleat (Vourlét corné), a; the nasal covering (la cuirasse nasale), b; 
the two subnasal flakes (/amelles), c; and the two transparent 
flakes, e, which cover the posterior part of the first ridge (bowrrelet). 
On the lower mandible, the two horny bands (lisérés cornés), f, and 
the chin-sheath (cuirasse mentonniére), g. 
“2. The anterior, or persistent portion, presents three ridges 
and three furrows, which I may designate (going from base to 
point) as the Ist or great ridge (I.), the 2nd or middle ridge (II.), 
the third or little ridge (III.); the Ist or great furrow (1), the 
2nd or middle furrow (2), and the 3rd or little furrow (8). Lastly, 
the beak is terminated by a smooth piece, forming a triangle with 
a curvilinear base, which I call the point of the beak (4). At the 
true popular name. Ornithologists, not understanding the allusion to the change of 
mask, would see only in the final Zauscher the German name for “ Diver,” der 
Taucher, ill pronounced. But I will venture no further on the dangerous ground 
of etymology, which is not my province, and I hasten to conclude with this 
simple reflection, which I submit to German naturalists:—If the Larventauscher, 
le Changeur de Masque, is the true name of Fratercula, it is only right that it should 
be restored; if not, it may well be bestowed on it, for it is impossible to express 
more accurately in one word the remarkable physiological phenomenon which 
characterizes this bird. 
