I04 THE BEGINNINGS OF IIFE. 



variations ^^ it is only to be expected that they should 

 attempt to offer some explanations as to the cause ot 

 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 ^ that ' 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 : — ' 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 



^ 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. 



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

 Foraminifera.* (Ray Society, 1862, p. viii.) • 



