A single egg is laid by the razorbill, and is placed in a cranny, sometimes in a hole several feet deep; occasionally the egg is deposited in a hollow on a rocky ledge, and in such situations razorbills and guillemots are found breeding side by side. The egg is large and handsome, the ground-colour white, spotted and blotched with different shades of blackish and deep reddish brown, and sometimes chocolate-colour. Both birds take part in incubating. An observer who has studied the habits of this bird says that in most cases the young fly down to the sea, usually early in the morning, and being once there, do not return to the rocks, as their wings are not then strong enough to enable them to mount upwards. ‘Sometimes,’ he writes, ‘when the young one is obstinate, the mother will take it by the back of the neck, and fly down to the sea.’ (_Zoologist_, 1871, p. 2427.) He adds that the parent teaches the young bird to dive by taking it by the neck and diving with it. The breeding season over, the birds do not return to the rocks until the next spring. Common Guillemot. Lomvia troile. Head, neck, and upper parts blackish brown; under parts white. Length, eighteen inches. * * * * * The common guillemot is the most abundant of the four species of auks which inhabit the British Islands. Less handsome and striking in appearance than the razorbill, in its habits it is just as interesting. It is found in the breeding season on all parts of our coasts where extensive rocky cliffs and headlands exist, and it has not been driven away by persecution. At some points on the coast, as at Bempton Cliffs and Flamborough Head, and at the Farne Islands, and other localities farther north, the guillemots are still exceedingly numerous; south of Yorkshire they have greatly diminished in numbers, and several of the old breeding-stations have been abandoned. On the sea their habits are similar to those of the razorbill: they swim, dive, and fly in strings in the same manner. In appearance the two species differ considerably. The guillemot has a dusky brown or mouse-coloured upper plumage, and a straight, sharp beak, very different to the massive weapon of the razorbill.