ing near his house. He was unaware that the writers he speaks of, were not wrong in what they had said of the Acadicus, and that he and they had different species in view, the habits of which were so different as to be noticed by him, yet not such as to lead him to detect their specific distinctions.

Of Mr. Audubon's inaccuracies, I will not here speak at any length, nor am I willing to be suspected of any sympathy with those who have sought, on this account, to detract from the transcendent merits of the great painter and student of nature. While, however, we honor all that was excellent, we may at the same time, without disparagement to his great merits, correct whatever mistakes may have crept into his works, and even be pardoned if we enjoy a quiet laugh over some conclusions, now known to be visionary, but which his exuberant imagination, now and then, led him to put into printed words. We will take only one instance.

In his account of the common Black-Poll Warbler (Dendroica striata), we find the following eloquent picture of the delight with which he first discovered the nest of this bird: "One fair morning, while several of us were scrambling through one of the thickets of trees, scarcely waist high, my youngest son chanced to scare from her nest a female of the Black-Poll Warbler. Reader, just fancy how this raised my spirits. I felt as if the enormous expense of our voyage had been refunded. There, said I, we are the first white men who have seen such a nest."

It seems almost too bad to apply the touchstone of sober reality to so charming an evidence as is here given of the whole-hearted manner with which this enthusiastic lover of ornithology devoted himself to his mission,

His warmth and gratification have a touch of true poetry. But when we know that Mr. Audubon's whole party started in the expedition from Eastport, in Maine, where they also spent several days before they commenced their voyage to Labrador, and that one of his party was a near resident to Eastport; and when we further know that all around Eastport, and especially on the islands, the Black-Poll Warbler is one of the most common birds, we must see at once how far a vivid imagination has supplied the material for his conclusions, and that they had but little foundation in reality.

We will not dwell here any further upon the statements occurring in Mr. Audubon's writings, not consistent with the facts, as now known to us, for our limits do not permit, and the instance given above will sufficiently answer as an example of the mistakes into which his oversanguine temperament occasionally led him. His errors, we are sure, are never intentional; his statements of facts, when he tells us they are his own, we can rely upon: but when he accepts the information of others, or draws inferences from insufficient data, it is then that his accounts must be received with more caution, and that he exposed himself to the unkind and bitter attacks, in which those who do not appreciate his real excellences, or who are too intolerant of what are, after all, only venial faults, spots on the face of a great luminary, have too often indulged.

A few words on our own shortcomings, and we will close these desultory remarks. The Oölogy of North America, Part I., gives several illustrations which subsequent investigations show to have been not so well authenticated as they were supposed to be when published. They are: The egg given as that of the Goshawk (Astur

AMERICAN NAT., VOL. I. 16

atricapillus), on the authority of a Western naturalist; that given for the egg of the Western Rough-Legged Hawk (Archibuteo ferrugineus), on the authority of the late Dr. Heermann; that of the Pigeon Hawk (Falco columbarius), the grounds for which supposition were given in full; and that of the Violet-green Swallow (Hirundo thalassina), on the authority of the late Dr. Webb.

Subsequent discoveries of well-authenticated eggs of all these birds, quite different from those figured, seem to show that in each instance there is an error in regard to their identity.

The egg figured for that of the Goshawk is, possibly, a very faint specimen of a Red-tailed Hawk's. The Swallow's egg may be that of Hirundo lunifrons, and that taken for the Pigeon Hawk's, that of a Cooper's Hawk. The egg given by Dr. Heermann as that of the Western Rough-leg, cannot now be determined. It evidently is not what it was supposed to be.

Without seeking to conceal the fact that four of the eggs figured in the Oölogy, appear not to belong to the places in which they are found, nor to wholly absolve the writer from so much of the responsibility as belongs to him, of having been led into errors by the mistakes of others, he may here state that in regard to the egg of the Falco columbarius, it was given as such at the time, with the full expression of grave doubts as to its authenticity. All the facts, all the contradictory evidence, were given with all possible care, and to the reader was given all the data in the writer's power, to enable him to form his own judgment. An English traveller, who was so fortunate as to procure specimens of undoubted eggs of this bird, has seen fit, in the pages of the

"London Ibis," to comment, with some impertinence, upon the want of good judgment shown in not accepting Mr. Audubon's testimony as positive, and as outweighing what seemed contradictory to it. It is a sufficient answer to all this, to here add that by not doing as this writer now suggests, supposing the case fully made out in favor of his views, another mistake was avoided. The egg figured and described by Mr. Audubon is, in my judgment, not that of this bird, but of the Sharp-shinned Hawk. My English friend was, therefore, a little fast, and his comments are not based upon quite so sure a foundation as he supposed. Another time, perhaps, he will confine himself to facts within his scope. In assuming that Audubon was ex necessitate right, he presumed beyond his ability to establish.

If, in the above pages, I have shown, however imperfectly, to all ornithological readers, how easy it is for the most careful and best intentioned to make mistakes, to be led into errors, to make wrong deductions, and to fail to see and to correct previous wrong conclusions; and if I shall succeed in impressing upon all students in Oölogy especially, the absolute need there is always of the most thorough identification of the bird to which their eggs belong, I shall have done all that I have sought to do. Never keep in your collection, except as a curiosity, an egg or nest which has not been identified. Above all, never guess at its parentage. Never name it without the most unquestionable evidence that you are right. While there are a few eggs that are unmistakable, there are more that you can never be sure of, save by positive knowledge of their parentage.

THE FOOD OF THE COMMON SEA-URCHIN.

BY J. W. DAWSON, LL.D.

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B

THOUGH this creature is so common on the north-eastern coasts of North America, the nature of its food does not seem to be generally known. In dissecting some specimens collected at Tadoussac, Canada, last summer, I found the intestine full of small round pellets, which proved to be made up of the minute confervoid sea-weeds that grow on submerged rocks, mixed with many diatoms and remains of small sponges. It would thus appear that the curious apparatus of jaws and teeth possessed by this creature is used in a kind of browsing or grazing process, by which it scrapes from submarine rocks the more minute sea-weeds which cling to them, and forms these into solid balls, which are swallowed, and in this state passed through the intestinal canal, where they may be found in all stages of digestion. The sea-urchin is thus a kind of submarine rodent, in so far as its habits are concerned. From these pellets the microscopist may, after digesting them in nitric acid, obtain great numbers of beautiful diatoms (or microscopic plants, for a long time classed with the Infusoria), which are collected by the animal with its food, and whose silicious crusts escape the digestive

The cut represents the Common Sea-Urchin or Sea-Hedgehog (Euryechinus drobachiensis Verrill), one-third of the natural size. A, the eating apparatus seen from above, forming an inverted cone, the apex consisting of the cutting "teeth" or plates, which project out of the mouth-opening, as the animal moves mouth downwards. The five teeth move towards the centre during the act of eating. B, the same seen rideways. C, a single tooth, the lower point forming the cutting edge. D, the same scen sideways, the hook at the upper end with the other four, serving to retain the apparatus (sometimes called "Aristotle's Lantern") in place.