_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 vertebrae 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 vertebrae 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 vertebrae 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 Vertebrae in certain Cetacea._ (Cephalic vertebrae excluded.) --------------------------------------------------------------------- | Authorities. | | --------------------------------------------------- | SPECIES. | CUVIER. RUDOLPHI. KNOX. J. HUNTER. HUNTER | | | (Glasgow.)| --------------------------------------------------------------------- | | | | | | | |1. MYSTICETUS. | | | | | | |Skeleton of the | | | | | | |foetus (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. BALAENOPTERA. | | | | | | |Gigantic Northern| | | | | | |Rorqual | | | 65 | | |