THE NARWHAL. 377 



« 

 white streaks immediately below the skin, which are drawn irregularly 

 over the whole body, and at a little distance appear as if they were 

 made by means of some sharp instrument. Nothing is known of the 

 habits of this curious animal, which is unknown to science, except by 

 means of the specimen above-mentioned. 



We may dismiss the remaining genera of the family with the remark 

 that Petrorhyncus and Neoxiphius are found in the Mediterranean 

 Sea, that Berardius has been seen near New Zealand, and DoLiCHODON 

 at the Cape of Good Hope. The genus Dioploodon in the Indian 

 Ocean is a very remarkable creature, judging from its solitary species, 

 Dioploodon Schcllcnsis. The skidl has two horn-like processes projecting 

 from the snout ; the vertebras are enormous in comparison with the ribs, 

 which are slender and short. The genus Lagonocetus inhabits the 

 North Seas, and EPIODON the South American waters. 



THE NARWHAL. 



The family ^Ionodontid.e comprises one genus of only one species, 

 but this is so remarkable and so peculiar as to fully justify the creation 

 of a family for it. 



GENUS MONODON. 



The Narwhal or Sea Unicorn, Monodon monoccros (Plate XXVIII), 

 is distinguished from all other whales by the possession in the upper-jaw 

 of two powerful teeth. As a rule, the tooth on the right-hand side is 

 rudimentary, while the other attains a length of seven to nine feet. This 

 curious weapon is placed perpendicularly in the jaw, is hollow within, 

 and twisted spirally from right to left. In the females it is only slightly 

 developed. The skull, too, is likewise unsymmetrical. The upper-arm 

 and fore-arm are joined so as to preclude motion, the flipper consists of 

 five fingeis of four or three ioints. The round head occupies one-seventh 

 of the total length of the creature, the eyes are deep set, a little higher 

 than the point of the snout, the ear is very small, the crescent-shaped 

 blow-hole is between the eyes, in the centre of the forehead. From the 

 blow-holes a tube leads to two large air-chambers. The dorsal fin is 

 wanting, and only indicated by a fold of skin, the pectoral fins are short 

 and oval, the tail forms two distinct flaps. The skin is soft, brilliant, and 

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