104 THE BEGINNINGS OF LIFE. 



variations 1 , it is only to be expected that they should 

 attempt to offer some explanations as to the cause of 

 the persistence of so many of the very lower forms 

 why, in fact, these particular representatives have not 

 undergone any notable evolutional changes during 

 this long succession of ages. We are told by 

 Dr. Carpenter 2 that c there is strong reason to regard 

 a large proportion of existing Foraminifera as the direct 

 lineal descendants of those of very ancient geological 

 epochs/ on account of the great resemblance existing 

 between the fossil remains of the latter and the organ- 

 isms met with at the present day. He thinks their pro- 

 genitors may be traced back even as far as the upper 

 Triassic rocks. If we turn now to the reasons offered 

 for this long-continued essential similarity, we find 

 Dr. Carpenter writing as follows : c It can scarcely be 

 questioned that such a continuity of the leading types 

 of Foraminifera, maintained through so long a series of 

 geologic periods, and the recurrence of similar varietal 

 departures from these types, are results of the facility 

 with which creatures of such low and indefinite organi- 

 zation adapt themselves to a great diversity of external 

 conditions; so that, on the one hand, they pass unharmed 



1 Instead of having recourse to a special creative fiat or miraculous 

 intervention, in order to account for the presence of each separate kind 

 of animal or plant. For a comparison of the evidence bearing respec- 

 tively upon these two hypotheses, we may refer the reader to Mr. Spencer's 

 Principles of Biology,' vol. i. pp. 333-345. 



2 In the very interesting Preface to his 'Introduction to the Study of 

 Foraminifera.' (Ray Society, 1862, p. viii.) 



