1883.] on Wliahs, Past and Pnsent, and their Probable Oritjin. 375 



liiud-limbs iuto iustruments of propulsiou tbrougli the water; for 

 tlioii2;li the thifjhs and leij^s are small, the feet are lartre and 

 ai*e the special organs of locomotion, the tail being quite rudi- 

 mentary. The two feet applied together form an organ very like the 

 tail of a fish or whale, and functionally rej)resenting it, but only 

 fimctionally, for the time has I trust quite gone by when the Cetaeea 

 were defined as animals witlT the '• hinder limbs united, formiui: a 

 forked horizontal tail." In the whales, as we have seen, the hind- 

 limbs are aborted and the tail developed into a powerful swimming 

 organ. Xow it is very difiicult to suppose that when the hind-limbs 

 had once become so well adapted to a function so essential to the 

 welfare of the animal as that of swimming, they could ever have 

 became reduceil and their action transferred to the tail; — the animal 

 must have been in a too helpless condition to maintain its existence 

 duriui: the transference, if it took place, as we must believe, gradually. 

 It is far more reasonable to suppose that whales were derived from 

 auimals with lariijje tails, which were used in swimmimr. eventually 

 with such efiect that the hind-limbs became no longer necessary, and 

 so gradually disappeared. The powerful tail, with lateral cutaneous 

 flanges, of an xlmerican species of otter [Pteronura sandbaehii) or the 

 still more familiar tail of the beaver, may sjive some idea of this 

 member in the primitive Cetaeea. I think that this consideration 

 disposes of the principal argument in favour of the whales being related 

 to the seals, as most of the other resemblances, such as those in the 

 characters of theii" teeth, are evidently resemblances of analogy related 

 to simihu'ity of habit. 



As pointed out long ago by Hunter, there are numerous points in 

 the structure of the visceral organ of the Cetaeea far more resemblino; 

 those of the Ungulata than the Carnivora. These are the complex 

 stomach, simple liver, respiratory organs, and especially the repro- 

 ductive organs and structures relating to the development of the 

 young. Even the skull of Zeuglodon, which has been cited as pre- 

 senting a great resemblance to that of a seal, has quite as much likeness 

 to one of the primitive pig-like Tngulates, except in the purely 

 adaptive character of the form of the teeth. 



Though there is, perhaps, generally more error than truth in 

 popular ideas on natural history, I cannot help thinking that some 

 insight has been shown in the common names attached to one of the 

 most familiar of Cetaceans by those whose opportunities of knowing 

 its nature have been e:reatest — " Sea-Hoi^," ** Sea-Pig," or " Herrimr- 

 Hog" of our fishermen, Meersehwein of the Germans, corrupted into 

 the French '' Marsouin," and also " Porcpoisson," shortened into 

 " Porpoise." 



The ditiiculty that might be suggested in the derivation of the 

 Cetaeea from the Ungulata, arising from the latter being at the 

 present day mainly vegetable feeder's, is not great, as the primitive 

 Ungulates were probably omnivorous, as their legist modified descend- 

 ants, the pigs, are still ; and the aquatic branch might easily have 



