PREFACE. vii 



which Messrs. Parker and Rupert Jones had arrived from a careful comparative study of the 

 various forms of Numntulina iiroper. I liave endeavoured, as each genus came successively 

 under review, to specify what share in the special investigation of its characters is due to 

 my coadjutors, and what has been more particularly my own ; where no such intimation is 

 given, we may be regarded as jointly responsible. 



That our work will prove altogether satisfactory, either to the scientific or to the general 

 reader, is more than we can venture to anticipate. Those who look for precise definitions 

 will not find them here, for the simple reason that the conclusion has been forced upon us 

 \\\?i\,sliarply defined divisions — whether between species, genera, families, or orders — do not e.visf 

 amonr/ Foraminifera. And we are satisfied that any one whose study of tlie group shall have 

 been coextensive with our own must be ready to this extent to endorse our results. It has 

 been our aim, therefore, to set forth (so to speak) the fundamental " idea " of eacli of the 

 generic types we have adopted, rather than to attempt a precise limitation of its boundaries. 

 That some of our generic distinctions may be invahdated by more extended research, is just 

 as likely as that new generic types may present themselves among the collections from ocean 

 beds yet unexplored, or from geological formations as yet unscrutinised. The whole study 

 of this group must still be regarded as in its infancy ; and the utmost that we can hope for 

 this Introduction is, that it may help to give a riijht direction to that 'study. We have the 

 fullest confidence in the correctness of our general principles ; and shall not shrink from the 

 consequences of their application to our own work, however large a part of it may thereby be 

 superseded by something better. I have endeavoured throughout my own scientific career to 

 keep in view the noble character given by Schiller of the true pliilosopher, as distinguished 

 from the trader in science, that " he has always loved truth better than his system ; and will 

 gladly exchange her old and defective form for a new and fairer one." And the readiness 

 with which my coadjutors have accepted my amendments in the instances already alluded to, 

 affords the fullest assurance of their thorough participation with me in the desire, not only 

 that whatever is defective in our joint work may lie supplied, but that what is unsound may 

 be demolished, since what shall remain really good and true will then afford a firmer basis 

 for the future labours of otiiers. 



The study of the Rhizopod type in general, and of the Foraminifera in particular, has 

 peculiar features of interest to the Physiologist, the Zoologist, and the Geologist. 



If the views which I have expressed as to the nature and relations of their living sub- 

 stance be correct, that substance does not present any such differentiation as is necessary to 

 constitute what is commonly understood as " organization," even of the lowest degree and 

 simplest kind ; so that the Piiysiologist has here a case in which those vital operations which 

 he is accustomed to see carried on by an elaborate apparatus, are performed without any 

 special instruments whatever, — a little particle of apparently homogeneous jelly changing itself 



