The specimen was that of a young animal, and of the same species, I believe, as the one described by Mr. Hunter and Fabricius; it is a distinct species, and not merely the young of the Great Rorqual.
I shall return to the Dugong, as not being a Cetacean, in a future Section: its skeleton has been examined in a masterly way by De Blainville, an anatomist and observer of the highest order, since the time I wrote and published my Memoir on the Dugong.
The first great step in the anatomy of the Cetacea is unquestionably due to Cuvier; but his dissections were almost confined to the genus Delphinus, or the common Porpoise of our coasts. I repeated all his dissections, and found them, as they almost always were, scrupulously exact; but when I came to examine Cetacea with whalebone instead of teeth, I was surprised to find how different, in fact, the anatomy of the two great families was. Scarcely in any great natural family do we find Cuvier's favourite theory of anatomical and physiological co-relations so entirely at fault as in the Cetacea. The teeth or whalebone, as natural-history characters, lead to no results; the whole structure of the interior defies all à-priori reasoning. The brain in whalebone-whales does not fill the interior of the cranium; so that the capacity of the one is no measure of the solid bulk of the other. Their food is various, having no relation to the teeth or buccal appendages; vascular structures surround the spinal marrow, and extend in the Balænopteræ into the cavity of the cranium, which seem to be without any analogy in other mammals, or, at the least, a very obscure one, and whose functions are wholly unknown.
Cetacea might with some propriety be divided into whales with whalebone, and whales with teeth. Those with whalebone have rudimentary teeth in both jaws in the fœtal state. Fossil Cetacea exist, and they seem to have been of both kinds, but, no doubt, were generically and specifically distinct from the recent. Judging from the remains of those I have seen, I am inclined to think that those with teeth were of a stronger and firmer build in the skeleton than those called recent; that the neck was longer, and the caudal portion of the column shorter than in the recent kinds, and that they approached the Saurians in form. There is a remarkable want of symmetry in the crania of some of the Cetacea; but most remarkable is the cranium of the Narwhal. Of this fact I have already spoken, in the article published in the Transactions of the Royal Society of Edinburgh.
Delphinus Phocæna. Dissection of a small Cetacean sent to me from Orkney in the month of May 1835.—This species is said to abound on the coasts, and to furnish a kind of fishery to the inhabitants. On dissection we found 81 vertebræ, exclusive of the cephalic. The species must be quite distinct from those previously and subsequently examined by myself and many others, in which the number of vertebræ ranged from 61 to 66. It is also, I think, distinct from the specimen I saw in Dr. R. Hunter's Museum in Glasgow, in which the number of vertebræ was 90, exclusive of the cephalic in all the cases. Thus it stands with regard to the Cetacea called Porpoises and Dolphins.
In certain species of Delphinus the vertical column is composed of 61 vertebræ, in others of 65, in others of 66, in others of 81, in others of 90.
The specimen I now describe was, no doubt, that of a young animal; and the skeleton was prepared, consequently, as a natural one. This method has the advantage of security against the loss of any important osseous structures, which too frequently happens when the bones require to be macerated. The bones contained little oil, and weighed, head included, only 7¼ lbs.; the whole animal, when entire, weighed 14 stone, or 196 lbs.; the skeleton therefore was about a twenty-fourth part of the whole weight. It was a female. The external nostrils terminated in a single orifice of a semilunar shape, with the concavity turned towards the snout. Measurements of young animals have not the importance of those of the adult; but I give them here because I think that the specimen, although young, had nearly attained its full growth:—
| ft. | in. | |
| Total length over the dorsum | 6 | 5-2/8 |
| Total length lateral surface | 6 | 11-2/8 |
| Total length abdominal surface | 6 | 11-2/8 |
| From the snout to the nostrils | 0 | 11-4/8 |
| From the nostrils to the dorsal fin | 1 | 6-4/8 |
| Base of the dorsal fin | 0 | 11 |
| From dorsal fin to foot of tail | 3 | 0-2/8 |
| Breadth of pectoral limb | 0 | 4-4/8 |
| From the snout to the organs of generation | 3 | 9-4/8 |
| Circumference anterior to the arm | 2 | 9 |
| Circumference anterior to dorsal fin | 3 | 2-4/8 |
| Circumference posterior to dorsal fin | 2 | 10 |
| Circumference at setting on of the tail | 0 | 8-4/8 |
| Length of pectoral limb | 0 | 10 |
| Breadth of tail | 1 | 2 |
| Greatest height of the dorsal fin | 0 | 9 |
From the notes taken at the time, I find that my brother remarks that the Dolphin of Orkney differed a good deal in shape from those found in the Forth and seas in the South of Scotland. There were, moreover, 16 more vertebræ than in the skeleton of the Common Porpoise of authors. The teeth generally weighed 2½ grains each.