MAMMALIA. 55 



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FAMILY I. HERBIVOROUS CETACEA. 



No blow-holes ; pectoral mammae ; mustachios of hair ; an- 

 terior fins serving for prehension ; molars with flat crowns ; 

 sometimes tusks. One remarkable genus. 



MANATUS, Cuv. The Lamantins. 



Manati or Cow Whales have an oblong body; molar teeth, 

 marked with two transverse ridges upon their crowns; no 

 canines in adult age ; some traces of nails upon the end of the 

 pectoral fins ; skin very thick and naked ; mustachios very 

 strong and close. 



FAMILY II. CETACEA ORDINARIA. BLOWERS. 



Conical teeth, or none ; no vestige of hair; nostrils opening 

 without, on the top of the head, very far from the end of the 

 muzzle ; nasal fosses so arranged as to permit them to reject 

 by these openings the water which they take with their prey 

 into their enormous mouth. Four genera. 



GENUS I. DOLPHINUS, Lin. 



The general features which distinguish the Dolphins are 

 simple and few. They have teeth in both jaws, all simple, 

 and almost always conical ; these are the most carnivorous 

 and the most cruel of the order ; a dorsal fin always single ; 

 snout considerably elongated, broad at the base, round at the 

 extremity ,resembling the bill of a Goose. 



GENUS II. MONODON, Lin. Narwhals. 



The Narwhal has no true teeth in either jaw ; but in the 

 upper are found the distinguishing characters of the genus, 

 two long, straight and pointed tusks, like spears, spirally 

 twisted, implanted in the maxillary bone, and directed to the 

 front. 



Pectorals remarkably small for so large an animal, no dor- 

 sal fin, head about one seventh part of its whole length. 



GENUS III. PHYSETER, Lin. Cachalots. 



Under this genus we describe the Cachalot or Spermaceti 

 Whale. Head enormous and nearly square and generally 

 one-third of its whole body ; snout very obtuse and truncated; 

 lower jaw very narrow, containing teeth, none in the upper 



