Tongue and Teeth. In the inside of a bird’s mouth we find only one of the two things that we might expect to find: there is a tongue, but no teeth. We shall come back to the teeth immediately. The tongue is not so useful among the majority of birds as it is in most mammals. But some do make use of it to a great extent. If you watch a parrot eating its food, you will observe that its thick and fleshy tongue is of the greatest assistance in helping it to manipulate the pieces of food--to extract, for instance, the kernel from a seed or nut. It plays exactly the same part as it does with us. In one kind of parrot, called the ‘Brush-tongued Parakeet,’ the tongue is frayed out at the free end into a brush-like extremity. And there are some small birds, which peck at flowers and live upon honey, in which the tongue is thin and delicate, and frayed out in the same way; this allows them to suck up the juices of the flower. In the Hummingbird the tongue is rolled up so as to form two tubes running side by side, and the same power of sucking up juices is acquired by this means, which, curiously enough, is exactly paralleled by the proboscis of the butterfly. In other birds the tongue is sometimes merely a thin, flat, horny projection, and in others, again, it is just not absent altogether. A little reflection about the habits of birds will show that they really do not want teeth; and we know that Nature is a most rigid economist: nothing superfluous is allowed in the body. Even rapacious birds like Owls and Hawks have no teeth, because they have a powerful beak and claws, with which the food may be as effectually torn to pieces. Birds such as the Pigeon, which feed upon grain, possess a gizzard--which we have had something to say about already--that performs effectually the function of a mill, grinding into a powder the hard grains of wheat and other seeds which the bird swallows. Nevertheless birds once did possess teeth. In earlier times of the history of this earth there were some birds whose jaws had as formidable a range of teeth as the mouth of many reptiles. They were fish-eaters, and have been named _Hesperornis_ and _Ichthyornis_. The first was something like a Diver in shape, the latter more like a Gull. A still more ancient bird, the oldest form of bird known to us, the _Archæopteryx_, had also toothed jaws. In fact, in the old days it was the rule for birds to have teeth, whereas now it is the rule, without a single exception, for birds to be toothless. Perhaps these ancient and extinct forms had some corresponding disadvantage when compared with their modern representatives; their teeth and claws, for example, may have been less effective. But although there is no bird now living which has real teeth, traces of these organs have been discovered in the young embryos of certain birds, which seems to be an absolute proof that they, at any rate, had for their first parents toothed birds. But although