570 DE. CAEPENTEE'S EESEAECHES ON THE FOEAMINIFEEA. 



group of natural objects, in which such ready comparison of great numbers of individuals 

 can be made ; and I am much mistaken if there be a single specimen of Plant or Animal, 

 of which the range of variation has been studied by the collocation and comparison 

 under one survey of so large a number of specimens as have passed under the review of 

 Professor WILLIAMSON, Messrs. PAEKEE and KUPEBT JONES, and myself, in our studies of 

 the types to which we have respectively given our principal attention*. 



236. The general fact which I desire to bring prominently forward as the result of 

 recent investigations into this group, is, that in all the types possessing a wide geogra- 

 phical distribution, which have been specially studied by myself or by others, the range of 

 variation has also been very wide ; so that not only what would commonly be considered 

 as specific, but such as have been regarded as generic, and in some cases even as ordinal 

 differences, present themselves among organisms, which, from the intimacy of the 

 relationship that is evinced by the gradational character of those differences as well as 

 by the variations presented by the several parts of one and the same organism, must in 

 all probability have had a common origin. And it appears to me to be a justifiable 

 inference from this fact, that the wide range of forms which this group contains is more 

 likely to have come into existence as a result of modifications successively occurring in 

 the course of descent from a small number of original types, than by the vast number of 

 originally distinct creations which on the ordinary hypothesis would be required to 

 account for itf . 



237. The greater part of my First Memoir was devoted to the investigation of the 

 single type Orbitolites ; and I there showed that not only as regards the size, shape, and 

 other external characters of the organism as a whole, but even as regards the size and 

 form of its elementary parts (in which greater constancy might be expected), is there so 

 great a variation, the most marked diversities being apparent even in different parts of 

 the same individual, that all attempts to found specific distinctions upon such variations 

 are utterly futile. But further, I showed that a distinction on which almost any Natu- 

 ralist would feel justified in relying as of at least specific if not of generic value, that 

 between the simple type in which the chambers are arranged on only one plane, and the 

 complex type in which there are two superficial planes more or less strongly differentiated 

 from the median, is no less invalid. For although these types are usually distinguish- 



* I have the authority of M. DESHATES for the belief, that the excessive multiplication of generic and 

 specific distinctions which so greatly impairs the value of the late M. D'ORBIGKT'S labours upon this group, 

 was due to his having based these distinctions upon specimens selected for him as typical, and to his having 

 disregarded the transitional forms which any large collection of these organisms is sure to exhibit in 

 abundance, thus, to use the admirably discriminating phrase of the late Prince of CANINO, " describing 

 specimens rather than species." 



t In order to avoid misapprehension, I would here remark that the production of any organism seems to 

 me just as much to require the exertion of Divine Power when it takes place in the ordinary course of 

 generation, as it would do if that organism were to be called into existence de novo ; the question being in 

 reality, whether such exertion takes place in the way of continuous exercise according to a settled and com- 

 prehensive plan, or by a series of disconnected efforts. 



