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A NATURALIST ON THE "CHALLENGER. 



either coming from or going to the sea. There is only one 

 species of penguin in the Tristan group ; this is, Eudyjptes scdtator, 



GROUP OF " ROCK HOPPERS " AT INACCESSIBLE ISLAND. 



(From a photograph.) 



or the " well diving jumper." The birds stand about a foot 

 and a half high; they are covered, as are all penguins, with a 

 thick coating of close set feathers, like the grebe's feathers that 

 muffs are made of. They are slate grey on the back and head, 

 snow white on the whole front, and from the sides of the head 

 projects backwards on each side a tuft of sulphur yellow plumes. 

 The tufts lie close to the head when the bird is swimming or 

 diving, but they are erected when it is on shore, and seem then 

 almost by their varied posture, to be used in the expression of 

 emotions, such as inquisitiveness and anger. 



The bill of the penguin is bright red, and very strong and 

 sharp at the point, as our legs testified before the day was over ; 

 the iris is also red. The penguin's iris is remarkably sensitive 

 to light. When one of the birds was standing in our " work 

 room" on board the ship with one side of its head turned 

 towards the port, and the other away from the light, the pupil 



