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Published online by Cambridge University Press: 17 January 2013
The following observations as to the dentition of the Dugong were made rather more than two years ago, and the inquiry as to the succession and character of the teeth in this interesting animal, and as to the exact composition of its skeleton, was then fully gone into, and all the facts to be now stated proved satisfactorily to myself at least. Notices of these opinions and facts more or less perfect, have been in several ways submitted to the public, both in this country and on the continent; but, as the whole matter was in some measure controversial, tending to call in question the accuracy of a theory as to the dentition of the dugong, promulgated and supported by an anatomist of the highest reputation, I hesitated whether or not the matter to be discussed merited being brought before this Society. Recollecting, however, that the opinions and statements opposed to my own views, had found their way into the pages of a work, of such importance and authority in itself, as to impress readily in the minds of most readers an easy credence as to the exactness of whatever researches there find a place, I hesitated no longer as to the course to be adopted.
page 389 note * Sir Everard Home, Bart.
page 389 note † The Philosophical Transactions.
page 390 note * In the excellent anatomical account of the Lamantin, drawn up by Daubenton merely from a fœtus, preserved for some time in spirits, and under great disadvantages therefore, that careful observer first discovered and described the bifurcation of the heart, and partial separation of the ventricles of that organ from each other. A similar structure was afterwards found to exist in the dugong.
page 391 note * There are no proofs whatever that there now exists any where in Europe, a perfect skeleton of the dugong; by perfect, I mean a skeleton prepared under the immediate superintendence of an anatomist. The engraving of the skeleton in the Ossemens Fossiles, from which M. Cuvier drew up his account of the osteology of this interesting animal, represents it to be without a sternum. Now, it matters not whether the bones were sent home in this condition to M. Cuvier by the Naturaliste Voyageur, or whether the animal reached him entire, preserved in spirits, or otherwise, and the bones of the sternum were afterwards lost in preparing the skeleton; I insist chiefly on the fact, that the skeleton is, from some cause or other, imperfect. Extensive experience as to those matters has convinced me, that no skeleton can be properly prepared and in a way to be entirely depended on, with a view to anatomical and zoological inquiry, which has not been dissected and prepared under the immediate superintendence of a good anatomist. Mr Robison, who did me the honour to convey personally to M. Cuvier a memorandum from me, containing an outline of this inquiry, has since informed me that Baron Cuvier assured him that he now possessed five complete skeletons of the dugong; they must, of course, have come into his possession since the publication of the last edition of the “Ossemens Fossiles” in 1825; but it remains to be shewn before we agree to these skeletons being complete, by whom they were prepared, and if the separate bones were sent to Europe, or the entire animals
page 392 note * The animal to which the young skeleton I now speak of belonged, reached this country several years ago, and, as I have been assured, entire. It was the munificent gift of some patron of science to the Museum of the University. I many years ago pointed out, from a cursory and hasty view of the skeleton, when prepared, that a highly blamable neglect had been shewn in its preparation, inasmuch as the bones of the sternum and rudimentary pelvis had evidently been lost or destroyed. My brother, somewhat more than a year ago, having had occasion to re-examine this skeleton, discovered that the original teeth (probably all milk-teeth, as the skeleton must evidently have been that of a young animal) had been lost, and their place supplied by the workman to whom the articulation of this invaluable skeleton was entrusted, who had substituted for the absent teeth those of a variety of other animals, and even pieces of ivory. So that all that remains of this splendid gift is a mutilated skeleton, which ought not to be exhibited in any museum. I trust that nothing contained in this note will be construed by any one into censure of the Curators of a museum, which is really a private collection; on the contrary, we may regret with them that the person to whom they entrusted the dissection was found to be altogether unfit for real anatomical research. I mentioned these facts, first discovered by my brother, to several persons, and they, somehow or other, have got into the public journals; but this was not originally intended.
page 395 note * The difference in the tusks of the African and Asiatic Elephants is not confined to mere form; Mr Robison informs me that the ivory is much finer and more dense in the former than in the latter.
page 396 note * I observe, in a late number of the Annales des Sciences d'Observation that a new species of fossil Hyæna has been established, merely from a slight variety of form occurring in one of the molar teeth.
page 396 note † There is rather a vagueness in what Sir E. Home says about the milk-molar teeth in an animal four feet eight inches long; it seems reasonable to have expected that the molar teeth in such an animal should have been proved to be milk-molar teeth, by laying open the jaw and shewing the germs of the permanent ones below. The same distinguished anatomist has, besides, from an accidental oversight no doubt, given a representation of the upper jaw of a dugong, which must obviously have been adult, there being two molar teeth on one side, and three on the other, and has described this jaw as belonging to a young one, and has called these teeth milk-molar teeth.
page 399 note * The teeth in the true Cetacea, when present, are uniform.
page 401 note * All anatomists will readily admit the possibility that the mode of dentition of the narwal might be found, on inquiry, to differ from that prevailing in the ordinary Cetacea, inasmuch as the anatomical facts, and the inferences from them, cannot, as I had the honour to demonstrate to the Society on a former occasion, be transferred by à priori reasoning to any other species, even though that species be strictly congenerous: at least this has been the impression under which I have now, for a very considerable number of years, carried on extensive inquiries into the anatomical structure of animals. And here I may take the liberty of remarking, that this does seem to me to have been the impression under which all anatomists of any reputation have acted, notwithstanding the observations to the contrary which have been lately brought before this Society and the public, by a distinguished British naturalist, Dr Fleming; an erroneous conception of which, without doubt, must have arisen in his mind from his little acquaintance with anatomical science.
page 403 note * Mr Hunter, whose position in life enabled him more than any other person to investigate the structure of the Cetacea with advantage, has remarked, in those admirable “Observations on the Structure and Economy of Whales,” that he has availed himself as much as possible of all accidental opportunities of ascertaining the anatomical structure of large marine animals; “and, anxious to get more extensive information, engaged a surgeon, at a considerable expense, to make a voyage to Greenland in one of the ships employed in the whale-fishery, and furnished him with such necessaries as I thought might be requisite for examining and preserving the more interesting parts, and with instructions for making general observations; but the only return I received for this expense was a piece of whale's skin, with some small animals sticking upon it”—P. 372.
For my own part, I may say that all accidental opportunities of dissecting the larger species of whales in this country have been denied me by a curious arrangement, which I wish I could believe altogether accidental; for, notwithstanding the fact, very generally known, that all my leisure moments were constantly employed in ascertaining the anatomical structure of various animals, it has uniformly happened that the requisite information as to the stranding of any of the larger whales has been brought to me last. And thus has it happened with almost all the opportunities which have from time to time occurred for the anatomical examination of the rarer animals which have reached this country during the last ten years.
page 404 note * As I have not the honour of a personal acquaintance with the person into whose hands Mr Hunter's Papers came on the demise of that great man, I here take tne liberty of suggesting to him the propriety of publishing those Memoirs of the Cetacea spoken of by Mr Hunter, which assuredly will be found to contain highly important facts and observations.
page 406 note * British Animals.
page 406 note † The fœtus of a seal shortly before birth was found to be about 2 feet 6 inches in length, that of the mother being about 5 feet 2 inches.
page 407 note * In an Essay on the History of Whales, by the Honourable P. Dudley, Phil, Trans. 1725, the following observations occur as to the bulk of the fœtus of the Whale.
“Whalebone Whale.—This fish, when first brought forth, is about 20 feet long, and of little value: the full-grown animal is 60 or 70; say as 1 to 3.
“Spermaceti Whale.—The calf, or young whale, has been found perfectly formed in the cow when not above 17 inches long, and white; yet, when brought forth, it is usually 20 feet, and of a black colour.”
page 412 note * There is a species of Rhinoceros in which two incisive teeth remain below the gum during the whole period of the natural life of the animal: they are not to be seen then so long as the head is covered with soft parts. Thus the permanent residence of teeth within the alveolar cavities, or not visible beyond the gums, as assuredly happens in the narwal, and, as I supposed, might also occur in the case of the lower incisives in the dugong, is a fact not confined to the Cetacea.
page 412 note † An expression employed by M. Cuvier.
page 413 note * I have not observed the muscles in any of the whale tribe or Cetacea to stiffen, nor the blood to coagulate after death. Others, however, whose opportunities for observation may have been more extensive, may have noticed these phenomena. The muscles are, compared with other Mammalia, soft and easily lacerated. The anterior filaments of the spinal nerves are greatly more numerous or larger than the posterior.
page 415 note * I here take the liberty of subjoining a microscopical examination of the structure by Dr Brewster. “I have examined the piece of stomach you have sent me of one of the Cetacea. It seems, in its wet state, to consist of tubes or fibres, perpendicular to the two membranes which enclose them, thus: 
and the upper surface of one of the membranes is covered with hollows or depressions, corresponding with the extremities of the tubes or fibres. A more minute examination, conducted in a different way, proves these perpendicular portions to be tubes. In order to dry it, I pressed it between folds of paper, and the effect of the compression was, to press together nearly all the tubes, and make the whole one dense mass of a dark brown colour; but when it became dry, and slightly indu rated, I drew it out as if it had been India rubber, and the tubes opened and the the mass became white, thus*: 
page 415 note * See Edin. Phil. Journal by Dr Brewster.