UEPROUUCTION OF IIHIZOPODA. 33 



is so remarkable a characteristic of this group, would lead us to infer that, as every part of the 

 homogeneous sarcode seems possessed of the same attributes in regard to the pliysiological 

 activity of the individual, so it should be equally able to participate in that modification of 

 the ordinary processes of nutrition wliicii gives origin to new and independent beings by 

 continuous growth. There is evidence that this is actually the case ; for not only do portions 

 of the sarcode-body detached from the principal mass forthwith comport themselves after the 

 manner of that from which they have been separated, — the sarcode forced out by crushing 

 the shell of a living Arcella, for example, putting forth lobose extensions on the Amoeban type, 

 whilst that forced out by crushing the shell of a living Poh/.^foiJi<'lla puts forth the slender 

 branching pseudopodia of the Reticularian (Plate I, fig. 12), — but there is every reason to 

 believe that such detached portions can continue to maintain an independent existence. Thus 

 it is not unfrequcntly seen in AiiKcba that when a pseudopodial process or lobe of the body 

 has been put forth to a considerable length, and has become enlarged and fixed at its 

 extremity, the subsequent contraction of the connecting portion, instead of either drawing the 

 body towards the fixed point, or retracting the pseudopodial lobe into the body, causes the 

 connecting band itself to become more and more attenuated until it gives way, leaving the 

 terminal enlargement altogether detached ; and this portion speedily shoots out pseudopodial 

 processes of its own, and behaves itself in all respects as an independent Amce.ba. Still more 

 satisfactory evidence to the same effect has been obtained by myself in my detailed study of 

 Orbitolites ; for not only have I met with numerous specimens in which the loss of any portion 

 of the disk was repaired by a new growth taking place in every respect upon the regular type 

 (Plate IV, fig. 2(i), but I have been fortunate enough to obtain a specimen (fig. 27) in which 

 a new disk has been formed from what was obviously nothing else than a fragment broken 

 away from the margin of a much larger one. — Since, therefore, in the more as in the less 

 specialised types of Rhizopod conformation, any portion of the sarcode-body can thus 

 comport itself as an independent organism, it may be reasonably inferred that this is true 

 of the entire group, and that the detachment of such portions, after the manner of the 

 gemmation of higher plants and animals, is one mode in which Rhizopods are ordinarily 

 multiplied. And such would seem to be the most probable explanation of the appearances 

 seen by Schneider (xciii) in Dijliii/ut ; which indicate that a whole colony may be formed 

 by gemmation from the pseudopodial lobe of one individual. 



40. Inferential evidence to this effect is abundantly afforded by the study of the polytha- 

 lamous types of Foramiiiifera ; for in every case in which it has been hitherto possible to 

 examine the sareode-body of these animals, its character has been found to be uniformly the 

 same throughout, every segment precisely repeating every other, save in the difference of 

 colour already noticed, and in certain appearances occasionally presented by the outer 

 segments (^ 48), which are probably indicative of a more special kind of reproductive action. 

 The entire sarcode-body of an Orbitolites (Plate IV, fig. 14), for example, is made up of an 

 aggregation of segments that have been successively put forth, by a process essentially 

 resembling gemmation, from the primordial segment which continues to occupy the central 

 chamber; and it affords one of the best examples which the Animal Kingdom can present, of 

 that " vegetative'' or " irrelative" repetition which is an essential feature of all low grades of 

 organization. Every one of these segments, there is strong reason to believe, could maintain 



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