xii THE BELUGA AND NARWHAL 373 



The Beluga is a northern species purely. The reputed form, 

 D. kingii, was said to come from Australian seas; but there 

 seems to have been an error in this statement. It is interesting 

 to note that the white colour, so characteristic of the genus 

 and species, is not found in the young, which are blackish. They 

 gradually pale as they advance towards maturity. Delphin- 

 apterus leucas reaches a length of 10 feet, and like other 

 Porpoises will ascend rivers in search of food. It is said to 

 be specially addicted to salmon. Among the contents of the 

 stomach have been found quantities of sand. But this habit of 

 swallowing sand or pebbles has been noted in other Whales. 

 Whether it is or is not accidental (taken in with ground-living 

 food), it seems hardly likely that it is used for purposes of 

 ballast ! The Beluga has a voice ; but the name " Sea Canary " 

 is hardly suitable to it. A specimen of this species, recently 

 described from the shores of Scotland (it is often thrown up 

 upon our coasts), which had got entangled in the stakes of a new 

 net, was regarded by the natives, on account of its white colour, 

 as a ghost. Externally, besides its colour, the Beluga is remark- 

 able for possessing a distinct neck, which is correlated of course 

 with the freedom of the cervical vertebrae, and is also seen in 

 Platanistidae. 



The Narwhal (Monodon) is closely allied in structure to the 

 last genus. It has the following . anatomical characters : The 

 teeth are reduced to a single " horn " in the upper jaw, which 

 is rudimentary in the female. The neck vertebrae are free. The 

 vertebral formula is C 7, D 11, L 6, Ca 26. The pterygoids 

 are as in Delphinapterus, and, as in that genus, there are no hairs 

 upon the face or dorsal fin. 



This genus is of course most obviously characterised by the 

 twisted tusk of the male, which is occasionally double. This 

 tusk has given to the only species of the genus, M. monoceros, 

 both its generic and specific name. The animal has a spotted 

 colour ; but, as in the case of the Beluga, old animals tend to 

 become white. The use of its horn to Monodon has been 

 debated. In the first place it is clearly a secondary sexual 

 character. The males have been observed to cross their horns 

 like rapiers in a fencing match. It may be that they are used in 

 more serious combats. An ingenious suggestion is that the long 

 and strong tusk enables its possessor to break the thick ice and 



