150 NATURAL HISTOEY. 



THE INIA. OR AMAZON DOLPHIN,* is another of the remarkable fresh-water forms. The former 

 name is that given to it by the Indian tribes of Bolivia. It ranges from the mouth of the river up 

 the whole of its affluents of any magnitude, 2,000 miles from the sea. Mr. Bates, in his " Journey 

 on the Amazon," tells us that when it rises the top of the head is the part first seen ; it then blows 

 and immediately afterwards dips head downwards, its back curving over, exposing successively the 

 whole dorsal ridge with its fin. It seems thus to pitch heels over head, but does not show the tail fin. 

 It generally goes in pairs. Exceedingly numerous throughout the Amazons, it is nowhere more 

 plentiful than in the shoaly water at the mouth of the Tocantins, especially in the dry season. The 

 Indians have a story that the " Bouto," as they also call this creature, "once had the habit of assuming 

 the shape of a beautiful woman, with hair hanging loose to her heels, and walking ashore at nights in 

 the streets of Ega, to entice the young men down to the water. If any one was so much smitten as to 

 follow her to the water-side, she grasped her victim round the waist and plunged beneath the waves with 

 a triumphant cry." It is held in veneration, and on this account the Indians can hardly be induced to 

 harpoon it. They have a superstition that blindness results from the use of its oil (which nevertheless is 

 excellent for lamps), and though Mr. Bates prevailed upon an Indian to capture one, the fellow repented 

 of his deed the clay afterwards, declaring that his luck had there and then forsaken him. This animal is 

 seven or eight feet long. Its colour commonly is bluish above, passing into a pale flesh-colour beneath, 

 the tail and flippers being bluish, but the tints vary considerably, and even differ with age and season. 

 The head is furnished with a long beak. There is a kind of keel-shaped dorsal fin, and the nippers 

 are of fair size, broadish and tapering, tlms differing from those of the Susu. The skull has a certain 

 resemblance to that of the Gangetic Dolphin, but without the great cheek-crests peculiar to the latter, 

 besides other minor differences. In both jaws there is a long series of stout conical teeth of a pretty 

 uniform size. These vary in number in different specimens, as the following formulae in two separate 

 individuals show ^^'j=104; jj|r|^=131. The muzzle of the young is hairy; while both the eye and 

 the ear-hole are much better marked than in the Susu. It is a fish-eater, and the mother exhibits 

 .great affection and devotedness towards her young. 



THE PoNTOPORiA.t Like Inia this is a South American form, and is now known to inhabit the 

 mouth of the La Plata and other rivers entering into the Atlantic on the coasts of the Argentine 

 Republic and Patagonia. But, unlike the two preceding forms, it is not confined to the rivers, for it 

 ranges along the sea-coast. The very few specimens met with show it to be a small animal, not 

 more than fxmr feet long, of a blackish tint, pale beneath, with a white streak alcmg each side from 

 behind the blow-hole. It has an unusually long narrow beak, but not such a prominent head as in 

 the two others. This animal has a well-marked triangular dorsal fin, and the fore-flipper is somewhat 

 fan-shaped and broadish, and not pointed as in the Inia. The crestless skull has characters intermediate 

 between the river Dolphins and the marine Dolphins to be described farther on. The teeth are small 

 and very numerous, somewhat fewer in the young animal, conical in shape, with a swollen ring round 

 their base. The dental formula is as follows : =g= 212 ; or r=222. 



THE ZIPHIOID WHALES (ZIPHIID^). 



These singular Whales form a very compact group, closely united by common attributes, but they 

 are readily separated by definite characters from others. Until the beginning of the present century, 

 the Bottlehead (or Butzkopf) was that only known. Since then, at irregular intervals, chiefly solitary 

 individuals have been caught or stranded in various parts of the world ; but even now the numbers 

 coming under observation have been few. Their apparent comparative rarity in the present day is in 

 great contrast with the frequent discovery of their remains in the Norfolk Crag formations, where frag- 

 ments, principally of their dense solid beaks, show that they must have been at a long distant period 

 exceedingly numerous. On these grounds the supposition has been expressed that the present paucity 

 of forms is indicative of a survival of an ancient family that once played an important part in Nature. 

 The living forms range from fifteen to thirty feet in length, but their ocean habits are extremely ob- 

 scure. Their common chai-acters are long narrow beaks, elevated heads, a small but well-marked dorsal 

 fin placed behind the middle of the back, short flippers with rounded extremity, a pair of short throat- 



* Inia Geoffrensis. t Pontoporia Blainvillii. 





