LIVING FOSSILS. 153 



CHAPTER XV. 



LIVING FOSSILS. 



IN the preceding chapter it was pointed out how that, 

 through the discovery of the Australian lung-fish, the 

 ancient Secondary fauna of Europe was brought into much 

 closer connection with that of the present day than had 

 hitherto been supposed to be the case. This, however, is 

 by no means a solitary instance of the discovery in a 

 living condition of forms of life which have been regarded 

 as long extinct ; and since the subject of the survival of 

 ancient types in remote corners o the earth or the abysses 

 of the ocean is one of wide interest, we propose to consider 

 it in some detail in the present chapter. For such sur- 

 vivors from a distant past we venture to suggest the title 

 of "living fossils," seeing that for the most part they have 

 but little in common with the dominant fauna of the 

 greater part of the world; while their alliance with extinct 

 types is of the most intimate kind. It is, of course, 

 difficult to know where to draw the line in the use of such 

 an arbitrary designation ; but we shall endeavour to restrict 

 the term either to types which, although still more or less 

 abundantly represented at the present day, are of extreme 

 antiquity, or to such as are now represented by com- 

 paratively few forms, living either in distant parts of 'the 

 world or in the ocean depths, but which were abundant 

 in past epochs. Of those coming under the latter category, 

 the majority, as might have been expected, were first made 

 known to science from the evidence of their petrified 

 remains, while their existing relatives were not discovered 

 till later. Whether, however, the extinct or the living 

 types were the first to be discovered, the progress of 

 research has been gradually tending to connect the past 

 more intimately with the present than was originally 

 supposed to have been the case. 



Our first examples of " living fossils " will be taken from 



