THE PENGUINS 287 



which are somewhat like the penguins in appearance, bnt that 

 they come nearest to the petrels, or tuliinares, althongh the two 

 groups are so different in form. This makes it difficult to guess 

 what the ancestors of the penguins were like. 



Of the genera of living penguins, PygosccUs connects 

 Aptenodytes with Megadyptes, and this last genus may be taken 

 to represent the ancestral form of the other two. Spheniscus is a 

 specialised form of Eudyptula. So, if w^e try to draw up a 

 genealogical tree of the penguins, we must place Megadyptes and 

 Eudyptula near the base, and make Aptenodytes, Catarrhactes, 

 and Spheniscus occupy the apices of the branches. Paleontology 

 points to Megadyptes as the oldest living form ; but Mr. Pycraft 

 is of opinion that Eudyptula lies nearest to the ancestral .stock. 



As to the colour of the earlier forms of penguins, it may be 

 supposed that they were white below and dark on the back, head, 

 and throat. This last is inferred to have been the case, because 

 in Eudyptida the young in the down has the head and neck 

 brown, and it remains brown throughout life in all species of 

 SpJieuiscus. It is probably the same in Megadyptes, for in young 

 birds the feathers on the throat are brown, like those of the head. 

 In the royal penguin, also, the chin and throat are brownish in the 

 young. In all these cases, except Spheniscus, the chin and throat 

 subsequently become white, which, therefore, must be a late 

 acquisition. In the other species of Catarrhactes the young birds 

 in the down have the throat black ; then, with the first feathers, 

 it gets grey or nearly white, and then black again. Also the 

 species of PygosceUs have the chin and throat white when young, 

 but black when old. From all this we may infer that the black 

 throat in these species is due to atavism, and that their immediate 

 ancestors had white throats when adult. We may, therefore, 

 suppose that the royal penguin represents the earliest species of 

 the genus Caiarrhactes, and from it the others have descended ,- 

 and we may further suppose that the tufted penguin has been 

 developed from the crested penguin, because the plumes on the 

 head are so much longer ; so that we have the yellow-eyed penguin, 

 the royal penguin, the crested penguin, and the tufted penguin 

 as the probable line of descent. 



