PurrFin. NATATORES. FRATERCULA. 44] 
a month or five weeks, they are able to quit the burrow, and 
follow their parents to the open sea. Soon after this time, 
or about the second week in August, the whole leave our 
coasts, commencing their equatorial migration. At an early 
age, the bill of this bird is small and narrow, scarcely ex- 
ceeding that of the young Razor-bill at the same period of 
life ; and not till after the second year does this member ac- 
quire its full development, both as to depth, colour, and its 
transverse furrows. In Suaw’s General Zoology, Mr Srer- 
PHENS has given a figure, entitled the Northern Puffin, from 
a specimen ticketed Fratercula glacialis by Dr Leacu, in 
the collection of the British Museum, that was obtamed du- 
ring Captain Ross’s expedition to the northern regions, and 
which Tremmrncx also seems to think may be a distinct spe- 
cies. Now, as the difference between this and our own is 
stated to be in the superior size of the bill (the plumage be- 
ing precisely similar), I feel some hesitation in allowing it 
this rank, as I have found the bills of different individuals 
on our coasts to vary much in depth and curvature, .which 
circumstance may be observed in the present plate, contain- 
ing the figures of two birds killed off the Fern Islands ; in 
the one, which was taken in its burrow, the bill measures one 
inch and a-half in depth, in the other scarcely one inch. In 
length they are nearly equal, by which the mandibles of the 
larger-billed bird are made to appear much more convex 
than the other; and in the former, the keel of the lower 
mandible is also very strong and arched; in fact, this speci- 
men seems to possess the precise characters and relative pro- 
portion of bill of the Northern Puffin, figured by Mr Sre- 
PHENS. I may here add, that I have often obtained speci- 
mens with the bill of an intermediate size, which leads me to 
conclude, that this member does not obtain its full strength 
and dimensions till after the second or third year. On the 
water the Puffin is a more wary bird than the Guillemot, ge- 
nerally taking wing or diving before a boat can approach 
within range of gun-shot. It flies rapidly, but not to any 
