NARWHAL. 283 



although in two instances the teeth are greatly reduced in 

 number. The skull lacks the elevated crests behind the nasal 

 aperture which forms such a characteristic feature in the 

 Family last named ; while there are also differences in the 

 arrangement of certain of the cranial bones, as there are in the 

 conformation of the bones of the internal ear. In all cases 

 the aperture of the nostrils assumes a perfectly crescentic form, 

 with the horns of the crescent directed towards the muzzle. 



THE NARWHALS. GENUS MONODON. 

 Monodon, Linn., Syst. Nat. ed. 12, vol. i. p. 105 (1766). 



Head rounded, without a distinct beak; functional dentition 

 usually reduced to a single, spirally-twisted tusk of enormous 

 length in the left side of the upper jaw of the male, the 

 corresponding right tooth usually remaining undeveloped in 

 its socket, while, in the female, both such teeth are rudimental. 

 No back-fin; and all the vertebrae of the neck either completely 

 or partially separate from one another. 



The genus is represented solely by the under-mentioned 

 species. 



THE NARWHAL. MONODON MONOCEROS. 



Monodon monoceros^ Linn., Syst. Nat. ed. 12, vol. i. p. 105 

 (1766); Bell, British Quadrupeds, 2nd ed. p. 435 

 (1874); Southwell, British Seals and Whales, p. 106 

 (1881) ; Flower, ListCetacea Brit. Mus. p. 14 (1885). 



Narwhalus vulgaris^ Lacepede, Hist. Nat. des Cetaces, p. 142 



(1804). 

 Characters. Upper-parts dark grey, and under-parts white, 



both mottled with various shades of grey and greyish-black. 



Length of adult, exclusive of the tusk, from 14 to 15 feet ; of 



the tusk 7 feet, or more. 



Distribution. Essentially a denizen of the icy Arctic seas, the 



Narwhal has but little claim to notice here ; the only instances 



