GENERAL CHARACTERISTICS. 



In the embryonic condition all the whales 

 have very numerous rudiments of teeth, simi- 

 lar in form and structure to those of reptiles, 

 inclosed in a groove extending along the 

 whole length of the margin of the jaw, but 

 completely covered by the gum. But the 

 further development of these teeth is very 

 different in different cases. In some forms, 

 the true dolphins, they all cut the gum and 

 persist throughout life in very considerable 

 number. There are dolphins with more than 

 a hundred teeth in all. Others, such as the 

 killer-whales [Orca gladiator), have a com- 

 paratively small number, 44 in all, and in the 

 beluga or white whale the teeth in the upper 

 jaw disappear with age. In others, as in the 

 sperm-whales, the teeth cut the gum only in 

 the lower jaw, while the upper jaw remains 

 without teeth. In the bottle-nosed whales 

 iyHyperoodoii) only one tooth is developed in 

 each half of the lower jaw. In the narwhal 

 a single straight spirally-twisted canine attains 

 an extraordinary length, especially in males, 

 usually on the left side of the upper jaw. 

 Lastly, in the true or whalebone whales the 

 embryonic rudiments of teeth persist only for 

 a short time, but soon afterwards disappear 

 in order to permit of the development in the 

 palate of peculiar horny plates, known as 

 whalebone, of which we shall speak when 

 treating of that family. 



We thus find among the whales both a re- 

 duction in the number of the originally very 

 numerous but uniform teeth, and a disappear- 

 ance of the hind-limbs in consequence of 

 special adaptations. Manifestly all whales 

 had originally a considerable number of teeth; 

 manifestly they had all originally four limbs, 

 the hinder pair of which, however, has got 

 reduced to insignificant traces. 



The whales are not exclusively marine 

 forms. Some genera and species inhabit the 

 large rivers of South America and India. 

 But they are all so dependent on an aquatic 

 life that they pretty soon die if cast on the 

 shore. They are remarkably social, always 



found in numerous shoals or " schools," and 

 if several of the larger species are nowadays 

 to be met with only singly or in pairs, this 

 fact is traceable to the persecutions to which 

 these animals have been exposed. Except 

 in those cases the whales swim behind one 

 another in long rows, and since they always 

 come to the surface to breathe, and make a 

 great noise in doing so, these shoals can be 

 perceived both by the eye and ear at great 

 distances. Ungraceful and clumsy as these 

 animals appear when withdrawn from the 

 water, they are yet remarkably entertaining 

 by the agility and flexibility of their move- 

 ments in their own element. Incomparable 

 is the swiftness with which they dart like 

 arrows through the water without any great 

 exertion. No fish can be compared with them 

 in respect of the ease with which they assume 

 all possible positions, turn head over tail, and 

 scorn all obstacles to their progress. One 

 must have seen a shoal of large dolphins with 

 black backs and white bellies, as they are 

 often seen in the northern seas, playing round 

 the ship in heavy storms, diving under the 

 keel, showing sometimes the upper, sometimes 

 the under side, to form any idea of the enor- 

 mous muscular strength which these animals 

 have at their command. 



They migrate through wide expanses of the 

 ocean, and during these rapid journeys the 

 movements of the animals as they follow one 

 another are quite rhythmical. The top of the 

 head emerges for an instant above the water, 

 and at that moment the animal exhales and 

 inhales with a great noise. In the large 

 species the act of expiration produces a column 

 of vapour visible at a great distance, which 

 thus betrays to the fishers the presence of the 

 whales. I have seen large rorquals swimming 

 round our ship at the distance of a rifle-shot, 

 and have been able to satisfy myself that the 

 blow-holes rise entirely out of the water in 

 breathing, and that the appearance of a jet 

 shot up by a fountain begins only at some 

 litde distance above the head. This appear- 



