126 GENERAL HISTOEY OF THE INFUSORIA. 



and, presenting a thousand intermediate forms, they grow iato perfect 

 Euglencey After awhile these Euglence become encysted, and terminate in 

 the quiescent or ' Profococcws-condition,' and subsequently, by self-division 

 of the contents, are resolved into motile microgonidia which escape free into 

 the water. " If a number of these remain conjoined, and move about with a 

 rowing kind of movement, their locomotion being governed by a common 

 spontaneity, they represent a VoIvoxAj^q colony, which, perhaps, may even 

 have been described as VoJvox by authors. The microgonidia of the Eughna, 

 like those of all the Algae hitherto examined by me, are the motile parent- 

 cells of extraordinarily minute spiral filaments. They are at first green, 

 gradually becoming pellucid — exactly hke the spermatospheres of Spirogyra^ 

 presenting a Monadifonn aspect. A pecuhar appearance arises when many 

 microgonidia in such groups remain green wliilst the others have already 

 become clear as water ; the mass then presents, in fact, the aspect of being 

 composed of two kinds of animalcules. Such or similar conditions would re- 

 present several species of the supposed genus UvelJa (atomus, glaucoma, Bodo, 

 &c.). Each ultimately colomiess microgonidium, then, by the dissolution of 

 its minute gelatinous envelope, discharges a small motile spu^al filament." . . . 

 '' These spiral filaments do not appear to be destined for the purposes of im- 

 pregnation ; for they gradually increase in length and thickness, soon exhi- 

 bitiag numerous spiral tiu'us," and then exchange the Sinrilla-Yike for a 

 Sj)iruJ uia-f orm. "■ Finally, when their motile faculty has become weakened, 

 they afiix themselves by one extremity to any larger object near (for instance, 

 Conferva-filaments, &c.), whilst the other extremity continues to move about 

 with a creeping motion — the peculiar Oscillatorian movement, in performing 

 which a young filament frequently returns to the spiral. The last-described 

 condition constitutes the Leptothrix of authors. The filaments now graduallj' 

 become thicker ; and though at first of the hghtest emerald-green, they gra- 

 dually assume a deeper and deeper tint. The fii'st indications of articulation 

 are perceptible in them, until at last a young OsciUatoria is again perfected." 

 But the remarkable metamoq^hoses of this OsciUatoria are surpassed 

 by those of the Phytozoa of antheridia, as recounted by Prof. Hartig 

 (J. M. S. 1855, p. 51) : the antheridia of Marcliantia form the subject of 

 observation. Theii' Phytozoa fii'st assume the foim of Ehrenberg's genera 

 Spirillum and Vibrio, of which the most frequent varieties met with are 

 Vibrio rugula and V. prolifera ; '^ after twenty-fom' hours most of these 

 Vibrios and Spirilla — after forty-eight, all of them — have become disarticu- 

 lated." The whole di'op of water in which they float is now rendered 

 milky and turbid by numberless globules, similar to Monas crepusculum, in a 

 state of active motion ; and it is an important circumstance that Spirillum 

 does not originate from Monas, but always Monas from Spirillum. After 

 forty-eight hours, "^ groups of several hundi-eds may frequently be seen, in 

 which the primaiy active motion has ceased. Shortly aftei-wards a sharply- 

 defined hyaline skin is formed round these groups, and, as it would seem, 

 by the amalgamation or conjunction of the exterior molecules ; by this 

 means the young Amceba (Proteus) is formed. Tliis transformation takes 

 place pretty regularly towards the end of the thii'd day. The original size 

 of the Amceba is 1-300'" in diameter. In the course of three or four days, 

 it grows to about the size of 1-100'". This species diff'ers from the Amoebce 

 hitherto described, in the fact that the inner portion of the body which bears 

 the granules is much smaller than a certain hyaline coveiing, which covering 

 is closely attached to the hinder part of such inner portion, but extends far 

 away from the anterior part ; and, in addition to this, the progressive motion 

 in this species originates in an alternate enlargement of the longitudinal and 



