Reproductive Phenomena of the Amoeban Rhizopods. 331 



nuclei generally, I have detected no nucleolus, and the granular 

 mass of the nucleus has invariably filled up its own capsule. In 

 no example, whether amongst the youngest or most mature spe- 

 cimens, have I observed the nucleus (that is, the entire nuclear 

 cell and contents) attached to the ectosarc, or the granular 

 mass of the nucleus itself attached at one point to the interior 

 of the capsule containing it, — the granular mass being free, and 

 its component granules merely sustained within a matrix of 

 viscid protoplasm, although frequently these granules cling, as 

 it were, to the interior of the cell, just as the chlorophyll-gra- 

 nules of the vegetable cell, generally speaking, form a layer im- 

 mediately within the denser granular protoplasm which lines 

 and circulates within its interior. 



It will be seen, on reference to Mr. Carter's last paper in the 

 'Annals'* (October 1863, p. 254), that he now entirely relin- 

 quishes the character derived from the supposed anomaly in the 

 configuration of the nucleus, on which he so strongly insisted 

 in his reconstruction of the typical characters of Amoeba princeps, 

 and accepts, as the distinctive feature of that form, the villous 

 appendage and, as a matter of course, the novel phenomena in- 

 volved in the discovery of its presence in Amoeba villosa. Further 

 comment upon this is accordingly unnecessary. 



Another point on which my previous views have been mate- 

 rially strengthened by recent experience is the nature of the cir- 

 culation in Amoeba. I am more than ever convinced that this 

 is not a vital act, but a secondary and mei'e mechanical efi^ect 

 consequent on the inherent vital contractility of the sarcode. It 

 is only necessary to watch a specimen of Amoeba carefully, to 

 become convinced that the appearance of a returning as well as 

 an advancing stream of granules is illusory. The stream, it will 

 be observed, is invariably in the direction of the preponderating 

 pseudopodial projections. The particles simply fiow along with 

 the advancing rush of protoplasm. There is no return stream ; 

 but the semblance of one is engendered by one layer of particles 

 remaining at rest whilst another is moving past them. In 

 short, the effect is similar to that which would be produced were 

 an empty and transparent bladder or caoutchouc sac, containing 

 granxdar bodies of greater specific gravity than the viscid fluid 

 within which they were sustained, to be rolled along a plane 

 surface. In such a case it is obvious that only those granules 

 on the upper or free aspect of the sac would be carried onwards 

 — that, having arrived at the most advanced point, they would be 

 deposited, as it were, and remain stationary, as would also that 

 portion of the sac on which they rested, until the rest of the 

 mass should have flowed over them again, causing them now to 

 appear at the posterior extremity, when they would once more 



22* 



