Determination of Species.—The determination of species as regards the Cetacea is one of much difficulty; Cuvier met this difficulty by an appeal to anatomy. The number of vertebræ composing the vertebral column (exclusive of the cephalic) seemed to me a tolerably secure guide in the determination of species,—being aware, however, that some doubted the method, believing that the number of the vertebræ might vary, first, with the individual, secondly with the age of the specimen. I still continue to be of my original opinion, that the number of vertebræ comprising the vertebral column, properly so called, may safely be trusted in determining the species of the Cetacea; and with this view I drew up the following Table, excepting from it the genus Dugong, which I have never considered to be a Cetacean:—
Tabular View of the Number of the Vertebræ in certain Cetacea.
(Cephalic vertebræ excluded.)
| Authorities. | |||||
|---|---|---|---|---|---|
| Species. | Cuvier. | Rudolphi. | Knox. | J. Hunter. | Hunter (Glasgow.) |
| 1. Mysticetus. | |||||
| Skeleton of the fœtus (the cervical reckoned as 7) of the Mysticetus borealis, Greenland | 48 | ||||
| Adult Mysticetus, Whale of Commerce. | unknown | ||||
| B. Mysticetus australis, True Whale of the Cape Seas | 59 | ||||
| 2. Balænoptera. | |||||
| Gigantic Northern Rorqual | 65 | ||||
| Specimen of Rorqual described by Rudolphi | 54 | ||||
| B. rostrata of Fabricius; on the authority of Van Beneden: A. Rorqual | 48 | ||||
| Great Whale at Antwerp. Van Beneden. Species not stated | 61 or 62. | ||||
| The lesser Rorqual of the North | 48 | 46 | 46 | ||
| Great Rorqual of the Cape | 52 | ||||
| 3. Physeter. | |||||
| Sperm Whale or Cachalot | 60 | ||||
| 4. Delphinus. | |||||
| D. Delphis | 67 | ||||
| D. Delphis. In my museum | 81 | ||||
| D. Delphis. In the Museum of Dr. R. Hunter, Glasgow | 90 | ||||
| D. Delphis. Dissected by John Hunter | 60 | ||||
| D. Phocæna | 66 | 65 | 51 | ||
| D. Ebsenii. Van Beneden | 90 | ||||
In a late number of the 'Bulletins of the Royal Academy of Brussels' I find some valuable remarks in respect of these points by M. Van Beneden. He praises, and deservedly, no doubt, the exertions of M. Eschricht to collect a proper Museum of the Cetacea. It appears, according to M. Eschricht, that at no age whatever do we find in true whales (meaning, I presume, the Mysticetus borealis and australis) any distinct vertebræ in the cervical region as in other mammals. A fusion of all into one bone or cartilage seems to take place even in the youngest fœtus. In the fœtus examined by me of this species (a specimen removed from the uterus of a true Mysticetus killed in the Greenland seas), I do not recollect the precise appearance of the cervical vertebræ; but the skeleton is in existence, and shall be referred to. To the skeleton of the Rorqual now in the Museum at Antwerp, and which seems to me of the same species as the one I dissected in Scotland (and of which the skeleton, prepared with infinite care by my brother and myself, was presented by me to the Town Council of Edinburgh, and is now preserved in the Zoological Gardens of the same city), he gives the following vertebræ:—
| Skeleton of the Rorqual at Antwerp— | Cervical | 7 |
| Dorsal | 14-15 | |
| Lumbar | 15 | |
| Caudal | 25[C] | |
| Total | 61 or 62 |
In the skeleton of the Great Rorqual now in the Zoological Gardens at Edinburgh, and originally dissected and prepared by my brother and myself, these vertebræ are—
| Cervical | 7 |
| Dorsal | 15 |
| Lumbar and Caudal | 43 |
| Total | 65 |
In that of the Lesser Rorqual I dissected in 1830, the skeleton of which I think is still preserved in the Museum of the University of Edinburgh, we found—
| Vertebræ. | |
| Cervical | 7 |
| Dorsal | 11 |
| Lumbar | 13 |
| Caudal | 17 |
| Total | 48 |