From the learned observations of M. Audouin on this class, it must have happened that the animals in the sacs which he examined, and has called Achlýsia, were in an early stage of growth; so that he had no opportunity of ascertaining what I, under more favourable circumstances, discovered.

Whether the metamorphoses of the Hydráchnadæ be known, I am not aware; but it will be very remarkable should they be parasitic in their different states; and it struck me, at first, as an extraordinary fact, that these animals should remain in their sacs attached to the Dytíscus by their rostrum, when they are matured, and have eight perfect legs for use. I believe the Limnóchares are not uncommon in ponds and ditches, and are supposed to feed upon animalcula, &c. De Geer mentions, I believe, that the eggs of a Hydráchna are attached to, and receive nourishment from, one of the water fleas (Gyrìnus Lin.). — J. Curtis. 57. Upper Charlotte Street, Fitzroy Square, Nov. 16. 1833. [To Achlýsia Dytísci Aud. the text and figures in Zool. Journ. ascribe only six legs.]

Chélifer cancroides. (V. 754.) — I have often taken this odd little creature, and other species of Chélifer, attached to the legs of Músca doméstica, M. meteórica, and M. larvàrum. I have observed them attached to flies, most frequently in hot weather; but they are to be found, at almost any time, under the bark of trees, under stones, and amongst moss in dryish banks. The C. cancröìdes is known to live in old drawers and closets, and amongst old books. It is undoubtedly, at times, a parasitical creature; but not generally. They attach to the legs of flies by one of their curious pincers; but I have never seen them so attached as to lead me to believe that they derived nourishment from the flies. They feed, no doubt, in their usual habitats, on minute insects. W. B. B. W. Nov. 14. 1832.

Chélifer cancroides. (V. 754.) A fly (Músca doméstica) was yesterday produced to me, to one of whose legs were affixed four specimens of Chélifer cancröìdes. If this new instance can be called accidental, I am at a loss to conceive how so many enemies (as they doubtless are to its tribe) had attached themselves to one limb? If the fly had acci

dentally placed the limb in a nest of these insects, it seems natural to believe that it would have had sufficient sensibility to withdraw it ere the whole family had time to attach themselves. At present, the most probable reason which can be advanced is, that the fly was asleep at the time. I have to regret that a tender-hearted and fearful boy in the room should have stopped all further investigation on this interesting instance,

by crushing the little tyrants before I had time to complete my experiments on them.-F. C. Lukis. Guernsey, Aug. 7.

1832.

GEOLOGY. Additional Information on the Fucoides alleghaniénsis. (p. 27.)—Nov. 11, 12. 1833. Two days' examination along the slope of the Shade Mountain, in Juniata Valley, has materially enlarged my knowledge of the geological position of this fossil. On the banks of the Pennsylvania canal, near Lewistown*, the strata consist of numerous seams from 1 in. to 14 ft. thick, of argillaceous sandstone, more or less ferruginous, and varying in colour from dark brown to greenish blue. These are quarried in large slabs for the purposes of paving and building. The surfaces of these slabs are covered with Fùci in relief, whose forms are ill defined, and are smaller than the Fucoides alleghaniénsis; they are also separated by courses of soft argillaceous rock, from in. to 1 in. in thickness, consisting almost entirely of similar Fuci. An opening, made into another part of the series, at a lower position, and at the distance of half a mile, exhibited no fewer than a hundred successive courses of these vegetable deposits upon similar rock, within a section of only 20 ft. perpendicular. All these fossil beds comprise the same undefined Fucoides, occasionally traversed by the larger species. I traced a succession of these beds to upwards of 200 ft. elevation. At the height of full 350 ft., the Fucöìdes alleghaniénsis prevailed in abundance upon slabs of brown red sandstone, and probably extended 50 ft. higher. The whole series, therefore, which contains fossil Fúci occupies a thickness of from 250 ft. to 400 ft.

Nov. 21. 1833. In traversing the parallel ridges called the Seven Mountains, at the distance of 15 miles west of the Shade Mountain just noticed, the Fucöìdes alleghaniensis appears on the surface of white sandstone strata, occupying a mile in breadth, and rising to the height of 1000 ft.

Dec. 6. 1833. In Murney Ridge, 50 miles north of the Shade Mountain, and running parallel with, and at the distance of 15 miles east of, the Alleghany Mountains, I again observed splendid specimens of F. alleghaniensis.

I notice these localities, the detail of which is only interesting to show that this remarkable fossil is repeated at various and distant parts of the transition series in this country.— R. C. Taylor. Lewistown, Pennsylvania, Jan. 1. 1834.

* Upon this spot I observed growing that magnificent tree the Catálpa syringefolia, and groups of the medicinal shrub, Acàcia marilándica. At 400 ft. higher, the mountain was covered with the common acacia, or prickly locust tree (Robínia Pseud-Acàcia L.), amongst scrubby chestnuts and rock oaks and sumachs.

164

MISCELLANEOUS INTELLIGENCE.

ART. I. Retrospective Criticism.

REMARKS in Defence of [Mr. Audubon] the Author of the "[Biography of the] Birds of America" [VII. 66.], by the Rev. John Bachman, Charleston, South Carolina. Although, from my profession and habits, I feel no disposition to enter into controversy, yet, having had opportunities which few others possess of becoming acquainted with the occupations and literary acquirements of Mr. Audubon, and being prompted, not alone by feelings of private friendship, but by a desire that full justice should be awarded him for those expenses, sacrifices, and privations which he has undergone, I take the liberty of stating what I know on this subject; and I have reason to believe, from the characters of the writers who have doubted his veracity and the authenticity of his works, that, with the generosity of feeling so distinctive of those who are engaged in liberal and kindred pursuits, they will be gratified to assign him the meed of praise which he so undoubtedly merits.

It appears that exception has been taken to two publica-tions of Audubon's; one on the habits of the rattlesnake, and the other on the habits of the turkey buzzard (Cathártes Aúra). The latter publication is now lying before me; the former I have not had an opportunity of seeing; but, from what I gather from some communications in [this] Journal, it appears that he ascribed to the rattlesnake some of the habits of the common black snake (Cóluber constríctor Lin.), as ascending trees in search of game, feeding on squirrels, &c. He also mentioned the remarkable fact, of their living a considerable length of time in confinement without food.

[Here follows, in the manuscript, an extract of some length from Featherstonehaugh's Monthly American Journal of Geology and the Natural Sciences, Nov. 1831, p. 221. (the communication to that work to which Mr. Audubon, jun., has, in our VI.551., referred), and a variety of evidence from Dr. Cooper, Dr. Leitner, Dr. Randolph, and Mr. Hockley; the amount of which is, that "at least five well-defined species of rattlesnake are now found in this extensive country;" that rattlesnakes, of one or other species, climb and have been seen on fences, and on trees, and on bushes, and that one has been

seen coiled up and at rest, in the fork of a tree, at about 8 ft. from the ground; that "the rattlesnake sometimes takes to the water, and is found a considerable distance from the shore in salt water;" that the rattlesnake, in its native woods, feeds on squirrels; even, occasionally, on the largest American squirrel (Sciùrus vulpìnus), rabbits (Lèpus americanus), and also rats (Arvícola floridàna Ord, and, from the wording of the manuscript, probably other species of rat); and that, with regard to the means by which rattlesnakes capture these animals, it is possible that "rattlesnakes may yet be discovered to be nocturnal in their habits; possessing a degree of activity at night which is not exhibited by day, unless hard pressed by hunger." As this communication is professedly in reply to Mr. Waterton, who has, in VII. 67., line 8. and 7. from the bottom, observed that "nobody doubts that rattlesnakes swallow squirrels," it is needless to occupy space to confirm an assertion which Mr. Waterton has not disputed. The Rev. J. Bachman states that he had not seen a later number of this Magazine than the one for Sept. 1833. The MS. will be returned to the party through which it reached us, to be published elsewhere, entire, if our elision dissatisfies.]

With regard to the experiments of Audubon on the powers of smelling, usually ascribed to the turkey buzzard (C. Aúra) [VI. 84. 163.], I acknowledge that he has adopted views opposed to the long established opinions of naturalists. But no one who will read his paper on the subject, containing a full detail of a number of experiments on the habits of this vulture, can deny that, if he intended to deceive the world, he certainly chose a subject where detection was easy and certain. In our southern cities, these birds, with their kindred species Cathártes atràtus, are so abundant in our streets and on our house-tops, as to have become a nuisance. It is but due to Mr. Audubon to state, that, in his frequent visits to this city, he has fearlessly invited investigation on this subject. During his absence, he has written to me on several occasions, urging me to make farther experiments. A number of engagements prevented me from devoting as much time to the subject as was necessary to investigate it in such a manner as to prove satisfactory to my mind, and I postponed it to a more leisure period. On the recent visit, however, of Mr. Audubon to this city, I consented to institute these enquiries; in the prosecution of which I was aided by the intelligence and experience of such disinterested naturalists and men of science as could be obtained.

On the 16th of December, I commenced a series of experiments on the habits of the vultures (C. Aúra and C. atràtus);

particularly as regards their powers of smell and sight, which were continued, with little intermission, till the 31st. Written invitations were sent to all the professors of the two medical colleges in this city, to the officers and some of the members of the Philosophical Society, and such other individuals as we believed might take an interest in the subject. Although Mr. Audubon was present during most of this time, and was willing to render any assistance required of him, yet he desired that we might make the experiments ourselves, that we might adopt any mode that the ingenuity or experience of others could suggest in arriving at the most correct conclusions. The manner in which these experiments were made, together with the result, I now proceed to detail.

There were three points on which the veracity of Mr. Audubon had been assailed: first, whether the vulture is gregarious; secondly, whether he feeds on fresh as well as putrid flesh; thirdly, whether he is attracted to his food by the eye or the scent? To these queries, not only in justice to the American ornithologist, but to aid the cause of natural science, our enquiries were directed. First, whether the vultures of this country are gregarious? That vultures, during the breeding season, and occasionally at other times, fly singly, is well known; but such is also the case with all our birds that usually keep in flocks; witness the wild pigeon (Colúmba migratòria) and the robin (Turdus migratòrius), and many of our water birds. But that our vultures are gregarious, in the true sense of the word, is a fact well established. In most cases, in the interior of our state, as well as in the environs of this city, considerable numbers are found in company, from three or four to forty or fifty. They hunt for their prey in company; they feed together on the same carrion; they perform their gyrations in great numbers together, and they roost together. I have visited their roosting-places; a sight well worth travelling many miles to observe. In some deep swamp, or occasionally in high ground, surrounded by a thicket of vines and thorny shrubs, usually composed of Zizyphus volùbilis, and several species of Smilax and Rùbus, the buzzards resort for years together to spend their nights. Here, on some dead tree, and frequently on several that may be standing near each other, they are crowded so close together that one or two hundred may be counted on a tree, and frequently thirty or forty on a single branch. The ground and bushes, within a certain extent, are covered with the excrements; which, by their acridity, have destroyed the whole undergrowth of shrubs and plants and every blade of grass; so that the surface presents an appearance of having received several thick coatings of whitewash.