April, 1900.] 8^ 



- — I . » j i . » 



A LIST OF THE IRISH CRTACEA. 

 (WHAIvES, PORPOISES, AND DOLPHINS). 



BY R. F. SCHARFF, PH.D., BSC 

 (Plates 3 and 4). 



Whai^es and their allies were formerly a great puzzle to 

 naturalists owing to their fish-like external characters, 

 whereas their internal structure showed close affinity to the 

 higher animals. But everybody kno-svs now that they are not 

 fish. On account of their aquatic mode of existence, they 

 possess a remarkably fi.sh-like form — their front limbs being 

 paddle-shaped, while external hind limbs are entirely absent. 

 In all other respects, however, they agree with the ox, horse, 

 and also with man, and differ from fishes in breathing by 

 means of lungs; in being warm-blooded, and in bringing 

 forth developed young, which are fed with milk during the 

 earlier stages of their existence. Whales, porpoises, and 

 dolphins are, therefore, now classed among the milk-giving 

 vertebrate animals or mammals. 



We can distinguish two well-defined groups of these whale- 

 like creatures. The members ofthe/irst g^'oup, comprising a 

 single family {BaIcB7iidcE), possess no teeth ; but the absence of 

 teeth is compensated for by the development of the peculiar 

 elastic substance known as " whalebone." This whalebone is 

 of a horny nature, and is attached to the roof of the mouth, 

 from which it hangs in the form of a series of long narrow 

 plates, placed transversel}^ to the long axis of the mouth. 

 These constitute a kind of sieve-like wall on each side of the 

 mouth, through which the water is pressed when the whale 

 closes its mouth— thus imprisoning the small creatures which 

 find their way into it 



The members of the seco?id g7'oup are characterised by the 

 presence of teeth, and the consequent absence of whalebone. 

 As far as we are concerned, all the forms belonging to these 

 toothed whales can be classified into two families, viz., the 

 one including the sperm-whale and its allies {^Phys derides), 

 and another to which the porpoises and dolphins belong 

 {^DelphinidcB). 



Owing to the great difficulty of observing these large 

 creatures, the rarity of their capture on our shores, and the 

 meagreness of the descriptions given, we know less about 



A 



