THE PORPOISE 



(Phoccena communis) 



The Porpoise is far the most familiar Cetacean to British eyes, as it 

 is a common animal round our coasts ; it is also a fair average sample 

 of the Dolphin family {Delphinidce) to which it belongs — which family 

 includes about half of the whole Cetacean order, numbering some 

 three dozen species. 



The most noteworthy peculiarity differentiating the Porpoise from 

 its allies is the form of the teeth, which are heart- or spade-shaped 

 rather than conical and pointed, as in most Dolphins. They are very 

 small, and, as in this group generally, exceedingly numerous, and at 

 the same time variable in number, twenty-five or twenty-six on each 

 side of each jaw. As in all existing Cetaceans, they show no dis- 

 tinction into incisors, canines, and grinders. Their only use is to 

 hold the fish on which the creature feeds, which are bolted whole ; 

 the stomach is complicated, consisting of three compartments, of which 

 the first is much the largest, as in the stomach of the ruminants. 

 This kind of stomach is characteristic of the Cetacea, and it has even 

 been suggested that they chew the cud ; but no one has ever seen 

 them do so, and their teeth and jaws are never suitable for such an 

 action. 



It will be noticed that the Porpoise has a back-fin, which, it may 

 be mentioned, is different in structure from that of a fish, not being 

 supported by rays or spines, and the same applies to the tail-fin. 

 Porpoises vary a good deal in size, measuring from four to a little 

 over six feet ; their colour also shows some variation in the extent of 

 the black and white, and a creamy-white Porpoise, with the fins on 

 the back and tail edged with black, has been seen upon one occasion. 



The Porpoise is essentially a coast animal, often coming close in- 

 shore, and not found in the open ocean ; often, indeed, it ascends rivers. 



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