198 THE GEOGRAPHY OF MAMMALS 



peds, which are semi-aquatic ; (2) the Sirenia, or Manatees, 

 which are mainly aquatic ; and (3) the Cetacea, or Whales, 

 which never leave the water, and are wholly aquatic. We 

 will first consider briefly the principal representatives of 

 these three groups, following nearly the arrangement of 

 them employed in Flower and Lydekker's " Mammals 

 Living and Extinct." 



Section II. — Distribution of Pinnipeds 



The Pinnipeds, which we will take first, comprise three 

 distinct families — the Otariidte, the Trichechidx, and the 

 Phocidie. Beginning with the Otariidte, or Eared Seals, 

 commonly known as Sea-lions and Sea-bears, we find the 

 greater number of the species confined to the South Polar 

 Ocean, where they pass most of their time at sea, but, as 

 is well known, resort to the land at certain seasons for 

 breeding purposes. In the Atlantic Ocean, so far as is 

 known, the Eared Seals have never been ascertained to 

 occur much further north than the estuary of the La Plata 

 on the American coast, where the Patagonian Sea-lion (Fig. 

 41, p. 199) is met with, and the vicinity of the Cape on 

 the African coast, where Otaria jiusilla is found. But in 

 the Pacific, on the contrary, three distinct species of Otaria 

 are distributed all over the northern portion of that ocean. 

 Two species of Sea-lions are also met with in the Galapagos, 

 and they likewise occur on the coasts of Peru and Chili. 

 I think therefore we may assume that Otaria was origin- 

 ally an Antarctic form, but has travelled northwards along 

 the West- American coast and is now firmly established in 

 the North Pacific. In a parallel way in the Class of Birds, 



