CARPENTER ON EORAMISIFERA. 187 



And it appears to me 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 numbers of originally distinct creations which on the ordinary 

 hypothesis would be required to account for it.* 



The greater part of my first inemoir was devoted to the investigation 

 of a 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 specimen), that all attempts to found specific distinctions upon such 

 variations are utterly futile. But further, I showed that a distinction 

 on which almost any naturalist would feel justified in relying, as of 

 specific if not of generic value, that between the simple type in which 

 all the cells 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 

 distinguishable the one from the other without the least difficulty, yet 

 they are often combined in the same individuals, and this in such a va- 

 riety of modes, that the transition from the simple to the complex may 

 be clearly seen, by the comparison of a sufficient number of specimens, 

 to be by no means attributable to a mere advance of age. Further, 

 having been furnished (by the kindness of Mr. H. J". Carter) with spe- 

 cimens of the Scindian fossil which presents the characters ascribed by 

 M. D'Orbigny to his genus Cyclolina, I find, as I had anticipated, that 

 this genus is foimded upon a mere variety of Orbitolites, in which the 

 character of the surface-marking is more than ordinarily cyclical. Not 

 merely, however, does the range of variation of this type confound the 

 ordinary distinctions of systematists in regard to species and genera ; it 

 extends also to that difference in plan of growth which has been assumed 

 by M. D'Orbigny of such fundamental importance, as justly to constitute 

 the essential difference between his two orders Cyclostegues and Heli- 

 costegues. For, as I have shown, although Orbitolites is typically cy- 

 clical from its commencement, yet specimens frequently present them- 

 selves in which its early development has taken place so completely on 



D'Orbigny'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 contain in abundance ; thus, 

 to use the admirable discrimination of the Prince of Canino, " describing specimens ra- 

 ther than species.''' 



* 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 that exertion 

 takes place in the way of continuous exercise, according to a settled and a comprehensive 

 plan, or by a succession of disconnected efforts. 



