558 CETACEA. 



remaining for a long time under water. The aorta in the sperm- 

 whale is a foot in diameter, and the heart sends out at each 

 stroke probably ten or fifteen gallons of blood. The kidneys 

 are lobulated. The testes are abdominal and in contact with 

 the ventral body wall, at about the level of the anterior end of 

 the bladder, and there are no vesiculae seminales. The penis 

 is large and there is no os penis. The uterus is bicoanuate and 

 the placenta diffuse. The females bear a single (the smaller 

 species rarely two) young at a birth. There are two mammae, 

 inguinal in position ; the teats lying in depressions on each side 

 of the vulva. 



The Cetacea usually live together in herds (schools). The 

 smaller species frequent the coasts and some of them ascend 

 rivers ; others are mainly fluviatile. The larger species prefer 

 the open sea. They swim with great strength and speed, usually 

 keeping near the surface, to which they have frequently to ascend 

 for respiration. They can stay under the surface for a long time. 

 Some of the larger whales can remain submerged for more than an 

 hour, certainly for two hours and possibly for more. The spout- 

 ing or blowing of whales is not a spout of water ejected from 

 the nostrils, but is due to the condensation in the cold atmo- 

 sphere of the aqueous vapour of the column of warm and com- 

 pressed expired air, which issues with great force when the animal 

 reaches the surface. 



The Cetacea are carnivorous predaceous animals. Most of 

 them feed on small marine organisms and on fish and cephalopods. 

 The gigantic whalebone whales, which are without teeth, but 

 possess whalebone on the palate, feed on small floating marine 

 animals, nudibranchiate molluscs and jelly fish, etc. They 

 are animals of great intelligence and generally of a mild disposi- 

 tion. The cows display great affection for their calves, and it 

 is this feature which is often taken advantage of by whalers 

 in their pursuit of them, for the mother will rarely desert her 

 weaker offspring. If the latter is wounded or killed, the mother 

 will turn upon her pursuers with fury, and deal destruction 

 to the boats and death to the men. But it is rarely that whales 

 will attack men if unprovoked. The sperm-whale is apparently 

 an exception to this, for there appear to be several authentic 

 instances of a cachalot having attacked a ship and done it 

 severe damage, even sinking it. But in these cases it is pro- 



