membranous sac situated internal to the external thick one. This animal has one common sac, and thus differs from the orang-utan, which has two; the lungs also differ from those in the orang-utan in being subdivided on each side, the right lung having three, the left two lobes, as in the human subject. The extremities of the bones of the animal were cartilaginous.

London, January, 1832.

ART. V. Remarks on Incubation, in reference to those expressed in Professor Rennie's Edition of "Montagu's Ornithological Dictionary." By CHARLES WATERTON, Esq.

"I most earnestly entreat my scrutinise every inference." p. xxi. in said Dictionary.)

readers to weigh every fact, and rigidly (See the Professor's "Use of System,'

THE Professor tells us, in the last Number (p. 101.) of this Magazine, that "the terns, &c." (this "&c." is very vague) leave their eggs for whole days together." In his "Plan of Study," he informs us that the careful dabchick covers her eggs with a quantity of dry hay, mind, reader, to keep them warm till her return.

Now, the dabchick lays her eggs at the same time of the year that the terns lay theirs. The eggshells of the dabchick and of the tern are of the same thickness, as near as may be, and their contents are precisely of the same nature. If, then, the egg of the dabchick requires to be covered in order to keep it warm when the bird leaves the nest, that of the tern requires the same precautionary measure, for the same reason. Or, vice versâ, if the egg of the tern be left uncovered for whole days together, then, by a parity of argument, the egg of the dabchick might be left uncovered for whole days together. But the Professor tell us expressly, that, if the dabchick quits her eggs for a moment without covering them, their vicinity to moist plants, or to water, would certainly prove fatal to the embryo chicks.

From these two extreme statements of the Professor, first, that the terns leave their eggs uncovered for whole days together; and, secondly, that the dabchick covers her eggs with dry hay, if she leaves the nest for a moment, as their vicinity

See Mr. Owen's dissection of the Orang-utan, in No. L. of the Proceedings of the Zoological Society of London.

The larynx and a portion of the ulcerated intestine have been deposited in the museum of the Royal College of Surgeons in London.

to moist plants or to water would certainly prove fatal to the embryo chicks; I come to the following conclusion, viz. that the Professor knows nothing at all about the true reason why the dabchick covers her eggs when she leaves the nest. Wherefore I here enter my protest against this part of the Professor's "Plan of Study," as it cannot be of the least use to natural history. On the contrary, it will do harm. It is a mere exhalation of his own brain; a kind of "Will o' the wisp," which will lead his pupils into the swamp of error. No doubt his intentions are good; but it would be well to bear in mind "tantum ne noceas, dum vis prodesse videto.”*

I must here remark that the Professor tells us that it is in very warm weather when the terns leave their nests; still, it somehow or other so happens that during their breeding season the weather is often very raw and cold, and that there are sometimes hail-storms, and even snow.

In p. 101. the Professor asks if I mean to say that eggs, with chicks in them, can be left till they are "cold as any stone?" I mean to say no such thing, nor have I said any such thing. See my remarks, Vol. IV. p. 518. When I introduced "cold as any stone," I particularly alluded to the time of laying, before the bird begins to sit; and I asked the question, viz. if the new-laid eggs be covered with hay for the purpose of keeping them warm, during the absence of the bird from the nest for at least four and twenty hours. I have no need to attend to the Professor's suggestion of a thermometer and a stop-watch. He who thinks it worth while to read my remarks in Vol. IV. p. 517., on Professor Rennie's new edition of Montagu, will there see that I took up the pen for no other purpose but to expose the Professor's plausible, though at the same time very erroneous, theory, that the careful dabchick covers her eggs every time she leaves the nest with a quantity of dry hay, to keep them warm till her

return.

From the dabchick's nest in the bog, the Professor conducts his pupils to a carrion crow's nest, of course on the top of a tree. He says, "The carrion crow, for example, who lines her nest with wool and rabbit's fur, always covers her eggs with a quantity of this before leaving her nest, no doubt for the same reason that the dabchick employs hay."

Where, in the name of carrion, I ask, has the Professor learned that this crow covers its eggs with wool and rabbit's fur? Before I enter into the demerits of this whimsical statement of the Professor, I must here inform the reader that even waterfowl, whose nests are, comparatively speaking, but * "Beware of doing an injury whilst you wish to do good."

loosely put together, do not take any part of the lining or inside of them to cover their eggs when they leave their nests. You may see these birds, from time to time, while on the nests, stretching out their necks, and pulling towards them little bits of grass and drifting sedges; these they place all around them, on the outer rim of the nest. They cover their eggs with these materials when they leave the nest, and not with any part of the lining.

Now, if, as the Professor states, the carrion crow covers her eggs when she leaves the nest, how is she to act? Is she to fly off to the rabbit and the ram, for a fresh supply of fur and wool? Or is she to have recourse to the lining of the nest, which has been most beautifully formed and arranged with nice art before she began to lay? In this case she will be driven to the necessity of undoing part of the lining every time she leaves the nest, and on her return she must contrive to replace it before she gets upon her eggs; for, after she has once got upon them, you will see by the contour of the nest that she can do little or nothing more to the lining under her. On resuming her seat, she certainly does not push the fur and wool (our carrions here never use rabbit's fur), with which the Professor tells us she covers her eggs, to the outer edge of the nest, as the waterfowl do the bits of grass and sedges with which they cover their eggs; because, if this were the case, we should see these materials lying there when we ascend the tree. Now, I always know to a certainty that the carrion crow has forsaken her nest for ever, if I find, on mounting up to it, that any part of the lining is displaced and put on the outer rim. Some unlucky schoolboy or other enemy has been there, and either robbed it of its treasure, or done to it that by which the crow instinctively knows that it is neither safe nor profitable to return to it.

The real fact is, that the Professor's specious theory about the carrion crow covering her eggs with rabbit's fur and wool, for the same reason that the dabchick employs hay, simply comes to this, viz. that the carrion crow never covers her eggs at all, when she leaves the nest.

Last year, I had fifteen carrion crows' nests in the park ; some of them, by the by, upon very high trees. In the many visits which I paid to these nests, I could never find the eggs covered, though I looked pretty sharply after them, and pretty often into them.

Here I will stop for the present, and merely observe, that one day, on looking into the new edition of Montagu, and casting my eye on that part of the Professor's "Plan of Study" where he [p. xvii.] remarks that "most authors occasionally indulge

in fancying facts, instead of proving them by observation," I could not help thinking that this remark of his would prove a formidable weapon in the hand of any body who would wish to make a home thrust at the Professor of Natural History in King's College in the City of London.

Walton Hall, Jan. 7. 1832.

CHARLES WATERTON.

ART. VI. Dates and Remarks relative to the Migration of the Swifts in the Year 1831. By the Rev. W. T. BREE, M.A.

Sir,

HAPPENING to be under the necessity of making a journey last summer from this place, through London, to the Kentish coast, about the time at which the swifts take their departure, I had a favourable opportunity of noticing the appearance or non-appearance of these birds in the different parts of the country through which I passed. A plain statement of the result of my observations may, perhaps, prove acceptable to such of your readers as, like myself, take an interest in watching the migration of our Hirundines. The swifts appeared to have taken their departure early from this part of the country (Allesley, Warwickshire). I could only observe a single one here on the 31st of July: none had been seen by me for some days previous. I left home on the 1st of August; and, as I journeyed south-eastward, could perceive no swifts all the way till I came to Stony Stratford in Buckinghamshire (a distance of forty-one miles), where two appeared; and two more the same day, at Brickhill, one stage nearer to London. Many were to be seen at Crayford and Dartford in Kent, and near Gravesend, on the 4th of August; and in the evening of that day, I observed a very large assemblage of them sporting high in air, and uttering their "joyous scream" over the precincts of the latter town; they were to be heard again at the same place early in the morning of the 5th of August; and the same day, a few more appeared in one or two places between Gravesend and Dover. At Dover I could observe none till the 7th of August, when some five or six or more in a pack were to be seen and heard as they dashed round the ancient towers of Dover Castle, in the morning; and a few more in the evening, over the town and basin. I then lost sight of them entirely until the 14th of August; on the evening of which day, three, or perhaps more, appeared again

VOL. V. No. 24.

L

*

about the castle. These, I had calculated, would have been the last I should see for the season; but, to my surprise, a pair of swifts presented themselves to my notice on the 10th of September (none having been observed in the mean time between that day and the 14th of August), hawking about with other Hirundines just before dusk (a little after six o'clock), between the Marine Parade and the town of Dover.

From the above facts, it should seem that the swifts for the most part retire from the interior parts of our island considerably earlier than they do from places near the sea-coast; for they had entirely disappeared in Warwickshire by the 1st of August or before, as well as from the parts of Northamptonshire through which I passed on that day; while they were still found in considerable force at Dartford, Gravesend, &c., on the 4th and 5th of August; and some at Dover, on the 7th and 14th of that month. The pair that I observed on the 10th of September, there can be no question, were on their passage to more southern latitudes; and, like so many other travellers, had, no doubt, very recently arrived at Dover, where they rested for the night, with a view to embark for distant climes on the following morning. For it should be remembered that not one was to be seen at Dover for the space of nearly a month previously; and I looked for them on the 11th, and several following days, in vain.

It may not be out of place here, to mention that I am informed, on the authority of Mr. Le Plastrier of Snargate Street, Dover, that some years ago he discovered a swift alive, among the bells in the tower of St. Mary's church at Dover, in the winter. I much regret that my informant was unable to state the month in which this unusual fact occurred; but he is quite sure that it was in the winter, and that the bird was a swift. I am also assured by the same intelligent observer, that he recollects many years ago a similar instance of a swift being found in the winter among the bells of Stepney church. Mr. Le Plastrier's father had the care of the church clock; and on various occasions, when he went to repair or wind it up, was in the habit of being attended by his son, then a boy, who was an eye-witness of the above fact.

*This is the latest date at which I ever myself observed the swifts with us, save one, and that was the 15th of September, 1817, at Penzance; where and when two or three were seen under precisely similar circumstances: a few birds only, associating with the swallows and martins, observed just before dusk in the evening, on the sea-coast, remaining for one day only or part of a day, and appearing after an interval of a month or more had elapsed without a single one having been visible. (See " Table of earliest and latest appearances of Hirundines," Vol. II. p. 19. note f.)