MAMMALIA 



327 



together with mucus from the nostrils, is condensed into drops of 

 water in the cold regions, but the water taken into the mouth 

 does not pass out through the blow-hole. The nose is directly 

 connected with the windpipe, so that a whale can breathe while 

 swimming through the water with its mouth open. The eyes 

 are relatively very small, and there are usually no external ears." 

 (Traces of external ears in the porpoise are recorded by Professor 

 Howell.)^ The opening of the ear is minute. The cervical 

 vertebrae are very short and more or less fused. 



The skin is smooth and shiny, like coach leather, and a thick 

 coating of fat immediately underlies the skin. The blubber or 

 fat from whales yielded much profit from its oil until the modern 



Fig. 267. — Skeleton of a whalebone whale, and section of the mouth, 

 with whalebone: b, Blow-hole; a, upper arm; fa, forearm; h, hand; p, th, I, 

 small remains of pelvic or hip-bone, thigh, and leg; r, roof of the palate; 

 w, w, plates of whalebone;/, whalebone-fringe. (Holder's "Zoology," 

 American Book Co., Publishers.) 



method of getting oil from deep oil wells, and the scarcity of 

 whales has almost excluded the whale industry from the oil 

 trade. The toothed whales feed upon fish and larger marine 

 animals, while the whaleljone whales feed upon minute Mollusca, 

 jelly-fish, and Crustacea. 



The toothless whales are those in which the teeth, present in 

 the embryo only, are replaced in the adult by baleen or whale- 

 bone (Fig. 267), a horny product of the epithelium of the mouth, 

 which consists of a large number (from 330 to 370) of horny 

 plates hanging down like curtains in pairs, one on each side of 

 the mouth, nearly meeting each other in the middle, each pair 

 immediately behind another. The lower edges of these horny 

 1 Beddard, p. 346. 



