Moreover, if any doubts remained, they would be dispelled by the following evidence: in addition to the bare, yellow eggs there are some whose base is set in a tiny brown, pitted cup, obviously the work of either the Two-spotted Cryptocephalus or the Long-legged Clythra, according to the cage, but unfinished work, which half-clothed the egg, as it left the ovaries, and then, when the dress-material ran short, or something went wrong with the machinery, allowed it to cross the outer threshold in the likeness of an acorn fixed in its cup. Nothing could be prettier than this yellow egg, standing in its artistic egg-cup. Nor could anything tell us more conclusively where the jewel is manufactured. It is in the cloaca, the chamber common to the oviduct and the intestine, that the bird wraps its egg in a calcareous shell, often decorating it with magnificent hues: olive-green for the Nightingale, sky-blue for the Wheatear, soft pink for the Icterine Warbler. It is in the cloaca also that the Clythra and the Cryptocephalus produce the elegant armour of their eggs. It remains to decide upon the material employed. From its horny appearance there is reason to believe that the little barrel of the Taxicorn Clythra and the scales of the Four-spotted Clythra are the products of a special secretion; and, now that it is too late, I much regret that I neglected to look for the apparatus yielding this secretion in the neighbourhood of the cloaca. As for the thing so prettily wrought by the Long-legged Clythra and the Cryptocephali, let us admit without false shame that it is made of faecal matter. The proof is furnished by certain specimens, by no means rare in the Golden Cryptocephalus, in which the customary brown is replaced by an unmistakable green, the sign of a vegetable pulp. In course of time, these green eggs turn brown and become like the others, no doubt by reason of an oxidization which alters the natural qualities of the digestive product still further. The egg, entering the cloaca in a soft and utterly naked state, receives an artistic coat of the intestinal dross, even as the Hen's egg is covered by a shell formed of the chalky secretions. _Materiem superabat opus, nam Mulciber illic AEquora celerat_, said Ovid, in his description of the Palace of the Sun. The poet had precious metals and gems wherewith to build his imaginary marvel. What has the Clythra wherewith to achieve its ideal jewel? It has the shameful material whose name is banished from decent speech. And which is the Mulciber, the Vulcan, the artist-engraver that engraves the covering of the egg so prettily? It is the terminal sewer. The cloaca rolls the material, flutes it, twists it into spirals, decks it with chains of little pits and makes it up into a scaly suit of armour, showing how nature laughs at our paltry standards of value and how well able she is to convert the sordid into the beautiful.