172 NATURAL HISTORY SOCIETY OF DUBLIK. 



by myself, — in other words, by calling into play its own inherent con- 

 tractile power. 



It is true that Professor de Bary,* in speaking of the wonderful 

 phenomenon of the seeking out of the germ-cell on the part of sperniato- 

 zoids, and of the not less wonderful phenomenon of conjugation, suggests 

 that in the former instance the active ciliated spermatozoids, and in the 

 latter the conjugating protoplasmic masses, are impelled by a kind of 

 attraction exerted upon the other on the part of that which in either in- 

 stance is the receiving cell. But granting that the motive force impelling 

 in its normal direction the protoplasmic mass which actually passes over 

 may be an attraction on the part of the other (this indeed must be a 

 mutual attraction in those Conjugate which form their spores halfway), 

 yet this does not affect the modus operandi of the actual change of place, 

 that is, the means by which the locomotion is effected. In (Edogonium, 

 Sphseroplsea, &c, this presumed attraction, then, draws over into its 

 sphere bodies moving by cilia ; but in Spirogyra it acts upon bodies, if 

 I be right, moving their little distance in an amoeboid manner. In 

 either instance this presumed attraction may influence the ultimate di- 

 rection of the movement of the bodies acted upon, but cannot excite that 

 movement, nor can it affect the mode of progression. That it cannot 

 excite it even in Conjugate is certain, as in the case of the JVIesotaenium 

 observed by me, above cited, no such attractive force could exist : there 

 was no conjugation; and the exit of the "primordial utricle" with con- 

 tents was, so to speak, a purely spontaneous action, — a purely automatic 

 relinquishing of its previous apparently too narrow limits, and, as I have 

 above endeavoured to convey, by a kind of motion to all intents and 

 purposes " amoeboid" in its character. 



In all these cases active mobility is evinced by the protrusion of 

 what may be called indeed pseudopodal extensions ; and the result, as 

 in Amoeba itself, is not only change of form, but actual locomotion. 



It may be asked, where is the rolling, onward flow of the granular 

 contents in the Mesotsenium alluded to, and here, so characteristic and 

 conspicuous in my amoeboid bodies, and requisite to carry out the ana- 

 logy ? I believe the flowing movement of the contents in the latter is 

 due to its granular condition ; the granules, free and distinct from each 

 other, are urged on by the contractile power of the bounding protoplas- 

 mic mass; they therefore naturally assume a flowing movement, to a 

 certain extent resembling that of the blood-discs in the vessels of the 

 higher animals. In the latter instances, on the other hand, the contents 

 have not become at all so finely and freely disintegrated, and the whole 

 contents are simply compressed and so moulded by the contractile power 

 of the bounding protoplasmic mass as to become adapted to pass through 

 a comparatively narrow outlet. In both instances the solid contents 

 seem to be passive, and are urged along by the contractile power of the 

 external protoplasmic mass. In the one instance, the contents, loosely 



* " Untersuchungen iiber die Familie der Conjugaten," pag. 59. 



