CONCLTJDESTG SUMMAEY. 569 



appearing to present the same kind of transition from Sponges towards Foraminifera, 

 that, if my view be correct, is afforded by Carpenteria from Foraminifera towards 

 Sponges. 



233. The above reasons appear to me so strongly in favour of that idea of the essen- 

 tially spongeous nature of the animal of Carpenteina, which had been from the first 

 entertained by Dr. J. E. GRAY, as to leave me little room for hesitation in the belief that 

 such is its real character; so that, until the contrary shall be proved, we seem justified 

 in regarding this curious organism as a Rhizopod which in virtue of its shell is 

 foraminiferous, whilst in virtue of the animal body which that shell contains it is 

 spongeous. 



CONCLUDING SUMMAEY. 



[Added during the printing of the Paper.] 



234. In bringing to a close the present series of Researches on the Organization of 

 the Foraminifera, I think it desirable to combine a summary of the most important 

 results which I have obtained, with some remarks on their bearing, not merely on the 

 method to be followed in the attempt to frame a natural classification of this group, but 

 upon some of those higher questions relating to the origin and value of differential 

 characters generally, which have recently been brought prominently under the consider- 

 ation of the scientific world. In so doing it is my desire to confine myself strictly to the 

 scientific and practical aspect of these questions ; seeking in the first place to determine, 

 on the legitimate basis of induction, what general principles may be either certainly or 

 probably educed from the comparison of the large body of facts which have been 

 brought together by myself and others as regards the mutual relations of Foraminifera ; 

 and then briefly inquiring how far the results of similar comparisons made upon other 

 types of organized structure justify the extension of the same principles to the Animal 

 and Vegetable kingdoms at large. 



235. It may be well for me to advert in limine to certain features in this inquiry, that 

 render the group to which it relates singularly adapted for a comparison at once minute 

 and comprehensive amongst a wide range of individual forms. The size of the greater 

 part of these organisms is so small, that many hundreds, thousands, or even tens of 

 thousands of them may be contained in a pill-box ; and yet it is usually not too minute 

 to prevent the practised observer from distinguishing the most important peculiarities of 

 each individual by a hand-magnifier alone, or from dealing with it separately by a very 

 simple kind of manipulation. Hence the systematist can easily select and arrange in 

 series such of his specimens as display sufficient mutual conformity, whilst he sets apart 

 such as are transitional or osculant ; and an extensive range of varieties may thus be 

 displayed within so small a compass, that the most divergent and the connecting forms 

 are all recognizable nearly in the same glance. I am not acquainted with any other 



were transmitted by Mr. MACDOXALD to the Admiralty. I have not yet succeeded, however, iii obtaining 

 a sight of them. 



MDCCCLX. 4 P 



