AMPHIBIAN MILLIONS. 301 



ner, after an interval of a few seconds of submarine swimming, swift 

 as the flight of a bird on its course. Sea-lions and hair-seals never 

 leap in this manner. 



All classes will invariably make these dolphin-jumps when they 

 are surprised or are driven into the water, curiously turning their 

 heads while sailing in the air, between the "rises" and "plumps," 

 to take a look at the cause of their disturbance. They all swim 

 rapidly, with the exception of the pups, and may be said to dart 

 under the water with the velocity of a bird on the wing. As they 

 swim they are invariably submerged, running along horizontally 

 about two or three feet below the surface, guiding their course with 

 the hind flippers, as by an oar, and propelling themselves solely by 

 the fore feet, rising to breathe at intervals which are either very 

 frequent or else so wide apart that it is impossible to see the speed- 

 ing animal when he rises a second time.* 



How long they can remain under water without taking a fresh 

 breath is a problem which I had not the heart to solve, by insti- 

 tuting a series of experiments at the island ; but I am inclined to 

 think that, if the truth were known in regard to their ability of 

 going without rising to breathe, it would be considered astounding. 

 On this point, however, I have no data worth discussing, but will 

 say that in all their swimming which I have had a chance to study, 

 as they passed under the water, mirrored to my eyes from the bluff 

 above by the whitish-colored rocks below the rookery waters at 



* If there is any one faculty better developed than the others in the brain 

 of the intelligent Cattorhimis, it must be its " bump" of locality. The unerr- 

 ing directness with which it pilots its annual course back through thousands 

 of miles of watery waste to these spots of its birth small fly-dots of land in 

 the map of Bering Sea and the North Pacific is a very remarkable exhibition 

 of its skill in navigation. While the Russians were established at Bodega 

 and Ross, Cal. , seventy years ago, they frequently shot fur-seals at sea when 

 hunting the sea-otter off the coast between Fuca Straits and the Farallones. 

 Many of these animals, late in May and early in June, were so far advanced in 

 pregnancy that it was deemed certain by their captors that some shore must 

 be close at hand upon which the near-impending birth of the pup took place. 

 Thereupon the Russians searched over every rod of the coast-line of the main- 

 land and the archipelago between California and the peninsula of Alaska, 

 vainly seeking everywhere there for a fur-seal rookery. They were slow to 

 understand how animals so close to the throes of parturition could strike out 

 into the broad ocean to swim fifteen hundred or two thousand miles within a 

 week or ten days ere they landed on the Pribylov group, and, almost immedi- 

 ately after, give birth to their offspring. 



