502 Dr. W. B, Carpmter, [March 12, 



tliroiigli the vertical elongation of the segments, which, moreover, 

 are themselves partially divided into at least three distinct stories : 

 two, namely, which form the two surfaces of the disk, and an inter- 

 mediate one, which is very distinctly separated from them both. 

 Tlie former type of growth may be designated as the simple, the 

 latter as the complex. Now some Orbitolites seem to go through 

 their whole lives upon the simple plan, whilst in others the complex 

 plan shows itself in the very lirst ring ; and from the comparison 

 of such alone, it might be fairly supposed that these two plans are 

 characteristic of two distinct species. But when a considerable 

 number of these forms are examined, it appears that the simple 

 type may pass into the complex at any period of its growth ; the 

 same disk presenting the simple plan in the first 5, 10, 20, 30, or 

 more annuli, and the complex in all those subsequently formed. 

 Hence there can be no question that even so marked a diversity in 

 plan of growth is not in that case sufficient to establish a diversity of 

 specific type, but that the two must be accounted varieties only. 



A no less remarkable range of variation has been shown by 

 Prof. Williamson, and Mr. W. K. Parker, to prevail in other 

 groups of Foraminifera which they have particularly studied ; so 

 that it would appear as if this type of animal existence were spe- 

 cially characterized by its tendency to such variations. And this 

 will seem the more probable, when it is considered how little of 

 definiteness there is in the form and structure of the sarcode-body 

 that forms the shell ; so that the wonder is, not that there should 

 be a wide range of variation both in the form and in plan of growth 

 of the aggregate body, and in the mode of communication of the 

 individual segments, but that there should be any regularity or con- 

 stancy whatever. But it is only in the degree of this range, that 

 this group differs from others ; and the main principle which must 

 be taken as the basis of its systematic arrangement, — that of ascer- 

 taining the range of specific variation by an extensive comparison 

 of individual forms, — is one which finds its application in every 

 department of natural history, and is now recognised and acted on 

 by all the most eminent zoologists and botanists. There are still 

 too many, however, who are far too ready to establish new species 

 upon variations of the most trivial character, without taking the 

 pains to establish the value of these diff'erences by ascertaining 

 their constancy through an extensive series of individuals, — thus, 

 as was well said by the late Prince of Canino, " describing speci- 

 mens instead of species," and burdening science not only with a 

 useless nomenclature, but with a mass of false assertions. It should 

 be borne in mind that every one who thus makes a bad species, is 

 really doing a serious detriment to science ; whilst every one who 

 proves the identity of species previously accounted distinct, is con- 

 tributing towards its simplification, and is therefore one of its truest 

 benefactors. 



Some of the most interesting physiological and zoological con- 



