500 H. MARSHALL WAED. 



minutes. Two minutes later — i.e. at 5.5 o'clock — the vacuoles 

 had almost disappeared, a number of minute bright points, 

 slowly playing in the granular contents, probably representing 

 them. At this stage, also (c), the tip of the beak became 

 pale, diffluent, and began to protrude like a gelatinous drop. 

 Within five minutes later a large clear vacuole appeared in the 

 protoplasm at the end of the sporangium opposite the beak(c?), 

 and the pale swelling at the apex of the beak, suddenly 

 began to be inflated like a blown-up bladder. This con- 

 dition, at 5,10, ushered in the rapid changes depicted in fig. 16, 

 eto'h, all of which occurred within two minutes. The softened 

 apex of the beak {d) became rapidly distended into a vesicle, into 

 •which the granular protoplasm flowed smoothly and continu- 

 ously, evidently impelled from behind by the pressure of fluid in 

 the vacuoles. These vacuoles no doubt contained some soluble 

 material, excreted by the protoplasm, and an osmotic pressure 

 was thus established. The details are accurately figured as 

 they were observed : the rapid flow of the granules through 

 the axis of the beak (e), the distension of the pale (cellulose?) 

 apex into a larger and larger vesicle, becoming more and more 

 tenuous as the contents flowed in (f and ^), being very con- 

 spicuous. At length — at 5.12 — the last granules passed slowly 

 up the axis of the beak, and the former sporangium re- 

 mained as an exhausted case, in the cavity of which remained 

 a few minute granules, and a slight residue on the inner 

 walls, no doubt representing in part excreted material. The 

 walls of the emptied sporangium collapsed a very little, 

 and a large number of minute Bacteria could be observed 

 attached to the outer surface in all cases (k). Even as the 

 last granules passed slowly up the axis of the beak (h), 

 the slowly writhing mass of protoplasm began to divide up 



different trials: since the granular protoplasm, outer walls of the zoo- 

 sporangium, and the main part of the beak are practically constaut in appear- 

 ance, I drew a large number of outlines, and left the granules to be filled in 

 later. My attention could thus be concentrated ou the numbers, sizes, and 

 positiontj, &c., of the vacuoles, zoospores, and other details ; and these are 

 accurately represented in all respects. 



