ARCHElt — ON STEPHANOSPniERA PLUVIALIS (COHN). 161 



granules taking place into that most recently formed at the expense of 

 the others, the newest advancing always onwards beyond the others, 

 and thus was a rapid reptant movement executed (Figs. 4, 5, 6). Their 

 onward progress was often made in a tolerably straight line ; but, of 

 course, curves and sweeps, sometimes even somewhat abrupt, were 

 effected, the broader frontal margin being always carried in advance, 

 the attenuated extremity always at the posterior. 



In this way these amoeboid bodies travelled over the field with quite 

 surprising rapidity, crossing and recrossing each other in all directions. 

 Under a low power, insufficient at first sight to show the amoeboid or 

 " rhizopodous " mode of progression, these reptant bodies might pos- 

 sibly have momentarily called to mind so many minute green Planarige, 

 their crawling movement partook so much of a regular gliding cha- 

 racter. 



So rapid was the action of the pseudopodal extensions and that of 

 the onward flow of the general mass, and so energetic was the locomo- 

 tive power of these remarkable amoeboid bodies, that, not unfrequently, 

 one of these primordial cells which had fully assumed this condition, 

 prevented by some cause or other from becoming wholly extricated 

 from the old Stephanosphaera-globe, was actually able to drag about 

 along with it (like hermit-crab and his whelk-shell) not only the old 

 envelope-cell, but the perhaps still therein contained seven other more 

 or less changed primordial cells ; and, all the while, apparently not much 

 retarded nor materially incommoded by the incumbrance ! 



It may be worth while, en passant, to note the analogy in the diffe- 

 rentiation of the extremities of these amoeboid bodies with that of Dr. 

 "Wallich's lately described Amoeba villosa* — the tapering, faintly granu- 

 late, posterior extremity seeming to correspond to the villous rounded 

 organ in the actual Amoeba, described and figured by Dr. Wallich. 

 This appears at least a curious point in common. In both the narrowed 

 extremity was always posterior, the pseudopods always being given off 

 from the opposite or anterior portion, and in both, hence, the onward 

 progression was more direct than in most similar bodies, as well as 

 more rapid ; though, so far as I can see, if we could imagine one of Dr. 

 Wallich's Amoebae pitted against one of my Amcebiform bodies, the 

 former, I fancy, would have been beaten in the race ! 



I have indeed never seen any actual Amceboe, nor do I imagine any 

 body else, whose movements were so rapid, and power of locomotion so 

 vigorous, as those of these amoeboid bodies of Stephanosphsera. One 

 might almost fancifully imagine them endowed with a will, and in an 

 evident hurry to get somewhere, but unfortunately with a bad memory, 

 and always forgetting what their destination should be, or with what 

 object they set out ; or, as if they each had lost something, and all were 

 laboriously and diligently making the best use of their locomotive 



Ann Nat. Hist.," 1863, vol. xi., 2nd Ser., pp. 287, tt $eqq. 



