288 H. MARSHALL WARD. 



should the protoplasmic masses, once having become zoospores, 

 still hesitate (if the word may be permittted) before gro\vin<^ 

 on, and, having rested awhile, again become zoospores, but of 

 a different kind ? 



It might be suggested that the entire series of phenomena 

 should be connected and looked at in some such way as the 

 following : 



1st. The zoospore masses are formed, excreting a clear inter- 

 calary substance (primary cell wall of Strasburger), which they 

 then take up again. 



2nd. A more energetic separation follows, resulting in com- 

 plete isolation, passage out, and removal to a distance. This 

 active phase, though more energetic and lasting than the pre- 

 ceding, is in its turn superseded by a resting state, and the 

 protoplasm excretes the substances for a membrane. 



3rd. After the period of rest the protoplasm once more moves 

 actively (having left its membrane behind) as a still more ener- 

 getic zoospore — at least it moves for a longer period — -which in 

 its turn comes to rest, but only for a short time prior to 

 germination. 



4th. It then, having formed certain brilliant granules and a 

 cell wall, throws out a germinal tube at the expense of its con- 

 tents ; this soon dies if no proper matrix be at hand. 



Unfortunately this restatement of the matter does not seem 

 to help us. One can dimly see that the little protoplasmic 

 zoospore undergoes processes of activity and rest— possibly 

 partial exhaustion — and it is not absurd to conceive that some- 

 thing is gained by an active vacuolated stage. 



In Achlya — the above applies to Saprolegnia^ — the first 

 and second stages occur as before, only the second stage seems 

 to be less energetic, and the amoeboid bodies only succeed in 

 reaching the mouth of the sporangium. The third and fourth 

 stages are much the same. 



In the '•' Dictyuchus" form the second stage is still more 



> De Bary, however, says that both zoospore stages may become abnormally 

 suppressed, and the germinal tube be formed at ouee on leaving the sporan- 

 gium ; this increases the difficulty. Loc. cit., p. 94. 



