thickened, like what happens to the udder of females of the class mammalia, during the term of gestation. On comparing the state of the crop when the bird is not sitting with its appearance during incubation, the difference is remarkable. In the first case it is thin and membraneous, but by the time the young are about to be hatched, the whole, except what lies on the windpipe, becomes thickened and takes a glandular appearance, having its internal surface very irregular. It is likewise more vascular than in its former state, that it may convey a quantity of blood sufficient for the secretion of this substance, which is to nourish the young brood for some days after they are hatched. Whatever may be the consistence of this substance when just secreted, it most probably soon coagulates into a granulated white curd; for in such a form I have found it in the crop, and if an old pigeon is killed just as the young ones are hatching, the crop will be found as above described, and in its cavity pieces of curd mixed with some of the common food of the pigeon, such as barley, beans, etc. If we allow either of the parents to feed the young, its crop when examined, will be discovered to contain the same curdled

substance, which passes thence into the stomach (of the young), where it is to be digested." "The young pigeon is fed for some time with this substance only, and about the third day some of the common food is found mingled with it; as the pigeon grows older the proportion of common food is increased, so that by the time it is seven, eight, or nine days old, the secretion of curd ceases in the old ones, and, of course, no more will be found in the crop of the young.'

"It is a curious fact, that the parent pigeon has at first the power to throw up this curd, without any mixture of common food, though afterwards both are thrown up according to the proportion required for the young ones. I have called this substance curd, not as being literally so, but as resembling that more than anything I know; it may, however, have a greater resemblance to curd than anything we are aware of; for neither this secretion, nor the curd from which the whey has been pressed, seem to contain any sugar, and do not run into the acetous fermentation." (On Anim. Econ.)

Montagu calls this a milky or lacteal secretion, and rightly regards it as "common to

both sexes of the dove genus," and from our own observations we should say that the curd is mixed up with a fluid secretion in the crop previously to being transferred into that of the young,-nay, sometimes so abundant is this fluid that we have seen it drip from the bills of the old birds, both while feeding their young, and at other times.

Though nothing like this lacteous secretion for the support of the newly-hatched young is produced by any of the truly gallinaceous tribes, yet we must not suppose that it is altogether limited to the pigeons. Some, if not all of the parrots, as John Hunter observes, appear to be endowed with the same faculty, and it will, perhaps, be found to prevail amongst the passerine tribes more extensively than is suspected by naturalists.

Besides this great point of distinction between the columbine and gallinaceous birds, and the other grounds of dissimilarity to which we have adverted, the following may also be enumerated. Instead while drinking, of taking water into the mouth and elevating the head, in order to swallow, as we see the fowl do, the pigeon simply takes a continuous draught. White says "Most birds drink sipping at

intervals, but pigeons take a long-continued draught, like quadrupeds."

The hind toe, instead of being elevated on the leg, or tarsus, in the pigeon, is upon the same plane as the anterior toes; it is fairly pressed to the ground in walking, and embraces the roost in perching. Again, the wings are long, the quill feathers firm, and the flight remarkable for rapidity and endurance. To these rules there are certain exceptions, some of the more terrestrial species of pigeon being found to approximate in some degree, as it respects these particulars, to the gallinaceous tribes, while, at the same time, no one can mistake their true affinities. Two species of crowned pigeon* (Lophyrus) for example are known, both from the Moluccas, New Guinea, etc. Yet these large and heavy birds, almost exclusively terrestrial in their habits, and exceeding a fowl in size, are in essential structure true pigeons, though the wings and limbs approximate to those of gallinaceous birds.

We will not here enter into technical details, but we believe that, in a thorough examination of the internal organization, the

Both species have been kept alive (1845) in the gardens of the Zool. Soc.

opinion which goes to associate the columbine tribes into an order distinct from any other, will be found to be completely justified.

De Blainville places the pigeons in an order which he calls Sponsores. The prince of Musignano terms them Gyrantes, (in allusion to their circular flight.) In the "Museum of Animated Nature" they are termed Gyratores.

THE DOMESTIC PIGEON. The domestic pigeon is divided into almost innumerable varieties, from the high-bred carrier to the ordinary race of the dovecote; yet, diversified as they are in appearance, they are all, according to the opinion of those who have investigated the subject, descendants of the common rock dove,* (Columba livia.) To this opinion, were we not from experience aware of the difficulty of keeping up any remarkable strain in its purity, we should hesitate to subscribe; and we are not quite sure that there is not some ancient admixture of allied species, (as we believe to be in the instance of the dog,) whence, perhaps, arises a certain constitutional tendency to assume, at indefinite periods, varieties of form and con

* Not the stock dove, (Col. Ænas,) which is a forest or woodland bird, and has obtained its title in error.