354 



WHALEBONE 



'~^ 



a small Eorqual. But even these are larger than the majority 

 of Toothed Whales. 



The most characteristic feature by which the Whalebone 

 Whales are to be distinguished from other Whales is that which 

 gives to them their name, the presence of whalebone. Whale- 

 bone is a horny product of the epithelium lining the mouth, and 

 is comparable to an exaggeration of the transverse ridges which 



are found in the mouths of all 

 mammals upon the palate. In 

 non - Cetacean mammals these 

 ridges vary in depth, and are 

 arranged as a rule transversely, 

 l)ut with an oblique inclination. 

 This is precisely how the plates 

 of baleen are disposed in the 

 mouth of a Whale. Each piece 

 of " bone " is triangular in shape, 

 the broader end being that of 

 attachment while it narrows 

 gradually ; the inner side of the 

 blades is frayed out into a number 

 of threads which form the strain- 

 ing apparatus. The plates vary 

 in length up to as great an ex- 

 treme length as 13 feet, which 

 occurs in the Eight Whale at 

 times. The colour is black or 

 paler, even white. The number 



Bone of jaw ; b gum ; c, straight ^f ^;|-^ggg pj^tes in the mOUth is 

 edge of baleen plate ; a, e, frayed ^ 



out surface of baleen plates. (After vcry great. As many as 370 

 ^^^'^"■^ blades have been counted. They 



diminisli in length towards both ends of the series. Though 

 whalebone has been in use for a long period, whence the whale- 

 bone came was formerly one of those things not generally 

 known. 



A very prevalent notion was that the wlialebone formed tlie 

 eyelids or perhaps the eyelashes of the creature. Scaliger, com- 

 menting upon Aristotle, held that the whale had " lamellae upon 

 the eyebrows, which, when the head is plunged below the surface, 

 were raised by the water ; but when the animal raised its head 



t'iG. 189. — Section of upper jaw, with 

 baleen plates, of Balaenoptera. a, 



