THE WHALEBONE WHALES. 



'265 



whales each "blow" in a double stream, which is directed 

 backward toward the tail. 



Whales are rarely over fifty feet long; the sperm-whale 

 has been known to reach a little over twenty-three metres 

 (76 feet) in length, but Professor Flower questions whether 

 the sperm-whale frequently, if ever, when measured iii a 

 straight line, exceeds a length of sixty feet. The largest 



t^.— FiQ-whale. From Liitken's Zoology. 



of all whales, as of all existing animals, is the fin-back 

 (Fig. 302) or rorqual {Balmnoptera hoops), which some- 

 times measures thirty-four metres in length. The smallest 

 Cetacea are the porpoises. 



In the whalebone whales, the teeth, present in the em- 

 bryo, become reabsorbed into the gums before birtli and 



Fig. 303. — Outline of the cachelot, showing how the blubber is removed : ft, the 

 situation of the "case;" c, the junk; d, the bunch of the neck; h, the hump; 

 i, the ridge; fc, the small; /. the tail or flukes; between the oblique dotted 

 lines are the spiral strips or blanket pieces. 



are replaced by plates of wlialebone, three hundred of which 

 may be present on each side of the mouth. The inner 

 edges of these plates have projecting fibres, forming a rude 

 strainer; these whales feed on small iielagic jelly-fish, mol- 

 lusks, and Crustacea, by taking in a mouthful of water, and 

 then pressing the tongue against the roof of the mouth, 

 expelling the water through the openings between the 



