CETACEANS. 



353 



Carnivorous Cetacea. Sir E. Home in a Paper published in the 

 Philosophical Transactions(l ) descriptive of the teeth of the Platanista, 

 fDelphinus gangeticus), says of their structure that "the perfect 

 tooth has a tolerably sharp enamelled point, and the lower portion 

 has no enamel." This part which forms the implanted base, is 

 thickly coated by cement ; and the pulp-cavity is obliterated. The 

 summits of the teeth are worn or broken off rather suddenly, 

 beyond the tenth in the upper, and beyond the eleventh tooth 

 in the lower jaw ; these anterior teeth are worn by mutual attri- 

 tion, the upper ones on the posterior and inner part of the crown, the 

 lower ones on the anterior and outer sides, 



143. Physeter. — The outward and visible dentition of the great 

 Sperm-whale or Cachalot (^Physeter macrocephalusj is confined to 

 the lower jaw, the symphysis of which is co-extensive with four 

 fifths of the entire dental series. This series in the male Cachalot 

 consists in each ramus of twenty-seven subincurved conical, or 

 ovoid teeth, according to their state of development and usage ; 

 the smallest teeth are at the two extremes of the series (PI. 89, 

 fig. 1). In the young Cachalot they are conical and pointed ; usage 

 soon renders them obtuse, whilst progressive growth expands and 

 elongates the base into a fang, which then contracts, and is finally 

 solidified and terminated obtusely. 



In the lower jaw of a female Cachalot in Dr. Buckland's 

 Museum, the first and the last teeth have the pulp-cavity solidified ; 

 in the rest it is widely open, and the lower margin of the tooth 

 forming the base of the conical cavity is very sharp. From the 

 last or hindmost, the teeth gradually increase to the tenth, then 

 continue of equal size to the nineteenth, and again gradually diminish 

 to the twenty-second, counting forwards, that being the total number 

 in each ramus. My friend Mr. Broderip possesses a tooth of a 

 male Physeter, with the base open and uncontracted, which measures 

 nine inches and a half in length and nine inches in circumference and 

 weighs three pounds. (2) 



The teeth are separated by intervals as broad as themselves. In 



(1) 1818, p. 417. 



(2) An ingenious whale-fisher has ca rved in his leisure moments the chief incidents of his 



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