and Reproduction of the Polythalamia. 313 



separated chamber must also exhibit a similar one. But if I 

 could not find a large opening in many Orbulince, at which 

 Ehrenberg is so much astonished, especially as D'Orbigny had 

 already recognized and figured it (which, I may say in passing, 

 is not of the least importance in my eyes), I will only indicate 

 that possibly, after the Orbulina has been long swimming freely 

 about, the orifice may diminish, or become obliterated, and, 

 secondly, that perhaps a commencing obliteration of the orifice 

 of communication may be connected with the separation of the 

 last chamber of the Globigerina. In any case, as I must remai'k 

 in opposition to Ehrenberg, this orifice, which moreover has 

 also been missed by others*, is not of much importance, because 

 the whole surface of the Orbulina is permeated by innumerable 

 large and small pores, from which the protoplasmic filaments 

 issue; and these, as is shown by Polystomella strigilata, can 

 collect nutriment even without the reception of larger morsels 

 into the interior of the body of the llhizopod. 



5fC '1» 't^ 'T* ^^ •* 



I have recently incorporated some observations upon the 

 nature of the Rhizopod-body, in a memoir treating of cells and 

 protoplasm in the animal body, which will shortly appear in the 

 ' Archiv fiir Anatomic und Physiologic ' of lleichert and Du 

 Bois-Reymond, under tlie title of " On Muscular Corpuscles, 

 and what is to be called a Cell/^ I believe that in this I have 

 materially simplified the difficult question as to the nature of the 

 so-called sarcode of the body of the llhizopods, by proving that 

 this substance is to be regarded as identical with the protoplasm 

 of cells, with which it must then also share the name. This 

 may be the place to give some indications of the relationship of 

 the substances mentioned. 



Protoplasm is cell-substance, or, as the botanists say, cell-con- 

 tcnts-substance, but not always the whole substance of the cell- 

 contents. It is a thickly gelatinous mass, consisting of a homo- 

 geneous, limpid basement substance and imbedded granules, and 

 is albuminous in its chemical nature. In many vegetable cells, 

 especially of large size, the protoplasm of the cell separates itself 

 sharply from another, aqueous part of the cell-contents. The 

 aqueous part first makes its appearance in so-called vacuoles of the 

 protoplasm, until, by the farther growth of the cell, during which 

 the ])rotoplasm does not increase in pro])ortion, it fills the greater 

 part of the internal space. The protoplasm then forms only a 

 thin stratum on the inner surface of the cellulose-wall, envelopes 

 the nucleus, and stretches, usually in separate threads, through 



* Williamson says, at p. 2 of his work already referred to, that the 

 orifice is often not visible. 



Ann. ^ Mag. N. Hist, Ser.3. Vol.y'ii. 21 



