WHALES AND PORPOISES 



25 



foetus of the common porpoise the horny or bony tubercles on 

 the fin are larger and extend further. These tubercles are evi- 

 dently the last remains of an armature of bony plates which 

 covered the bodies of the early cetaceans. Distinct traces of 

 this armature were discovered by the German naturalist, Johannes 

 Miiller, in connection with the remains of the zeuglodon, that 

 primitive whale in which the teeth were still differentiated into 

 incisors, canines, and molars. It is possible, therefore, that when 

 the cetaceans branched off from some stock of primitive land 

 mammals allied to the modern edentates, they, like so many 

 existing edentates, had to a great extent replaced hair as a 

 covering for the skin by an armature of bony plates, hair only 

 remaining here and there on the under parts and about the 

 mouth, in which last position 

 it remains in so many whales 

 in the shape of a few bristles. 

 The Common Porpoise 

 rarely exceeds 5 ft. in length. 

 The colour of the upper parts 

 is dark grayish-black, with 

 black flippers and tail flukes. 

 The whole of the under parts 

 from the chin to the vent is white tinted with lemon or pink. 

 At the junction of the black of the upper and the white of the 

 under parts there is in many specimens a curiously distinct gray 

 line, as represented in my drawing. The eye in the porpoise is 

 relatively small. The external ear is represented by an opening 

 in the skin so minute that it is scarcely larger than a pin-point. 

 This aperture of the ear is situated about two inches behind the 

 eye, in a line with that organ, and is backed in some specimens 

 by a small wart, the vestige of an ear conch. The porpoise has a 

 voice, though it rarely utters cries except when in sore distress. 

 It is related by Thomas Bell (the author of A History of British 

 duadrupeds) that in the middle of the nineteenth century some 

 porpoises which had entered Poole Harbour made their way up 

 the little River Frome as far as Wareham, in Dorsetshire. Here 



Teeth of Porpoise (after Flower). 

 Magnified to twice natural size. 



