298 Dr. W. Pringsheim on the Germination 



capable of direct germination, while the third form of spore in 

 Achlya reminds one in the most striking manner of the above- 

 described moving spores of the SpirogyrcB. Here again are 

 formed inside the mother-cells of the resting spores, in rare 

 cases, instead of the ordinary large globular spores, smaller (like- 

 wise resting ?) spores of a form more resembling the well-known 

 moving spores of Achlya (PL IX. fig. 13) ; or these same smaller 

 spores are formed, after the complete development of the ordi- 

 nary resting spores, in the individual resting spores themselves and 

 from their contents. I was able to observe directly the germina- 

 tion of these daughter-spores in Achlya. Here, therefore, there 

 certainly exist three different forms of spores capable of germi- 

 nation, one of which originates, as in Spirogyra, by cell-forma- 

 tion in the contents of a form of spore likewise capable of ger- 

 mination *. 



These circumstances lead me to consider as certain the possi- 

 bility of the formation of various forms of spore in the same 

 plant, and out of the same contents destined for reproduction. I 

 have already mentioned, at the outset, that in each species, one, 

 as it were normal form, is distinguished, among the various pos- 

 sible forms of spore, by the preponderating frequency of its oc- 

 currence, from the other rarer and generally exceptionally pro- 

 duced forms. But that those rarer, or if it be wished, abnormal 

 forms, are nevertheless quite as capable of reproducing the pa- 

 rent plant, as the so-called normal form, appears to me quite be- 

 yond doubt, and for some, e. g. in Achlya, directly demonstrable. 

 That the formation of the abnormal forms is subject to as defi- 

 nite morphological laws, as the formation of the normal form, 

 follows from the regularity of the mode of their formation and 

 the constancy of their appearance. It moreover seems to me 

 probable, that the above- described production of moving, colour- 

 less spores, in large mother-cells possessing a bi-own nucleus, is 

 not limited merely to Spirogyra and (Edogonium, but perhaps 

 represents a very general type of formation of, in my sense ab- 

 normal— i. e. rare, merely appearing under exceptional conditions 

 of vegetation — forms of spore. I shall only add here, that I have 

 found exactly the same cells with detached coats and a brown 

 nucleus, somewhat as in e, fig. 8. PI. IX., in apparently dead cells 

 in Cladophora fracta also, and the exactly similar figured in 

 /, fig. 8, in decaying, still closed cells of young plants of Nitella 

 syncarpa. 



* I also observed in Achlya a division of the moving cells (figs. 14 a, b, 

 c, d, e) ; these often become consti-icted in the middle (fig. 14 h) instead of 

 germinating, after they have come to rest, and the two halves separate from 

 each other until perfectly (fig. 14 c, d, e) distinct, each then acquiring a 

 locomotive thread (cilia) and moving freely, like the mother-spore. 



