520 FETCH : 



fixed, and stages of its development were obtained under a 

 higher power. Tliree hours after leaving the drop the hypha 

 commenced to bend, and the contents showed segmentation. 

 Soon after this appearance the hypha became top-heavy and 

 fell back on to the surface of the drop. This was the signal 

 for the rapid Uberation of a chain of grayish rectangular 

 conidia, averaging 7 X 10 [i, from the distal end of the aerial 

 hypha. This behaviom' of the aerial hyphse was found to be 

 general, and, except round the edges, the surface of the drop 

 was speedily covered with ejected spores. The aerial hyphse 

 proved to be microconidiophores and the spores microconidia. 

 When first extruded from the hyphse the conidia are grayish 

 in colour, rectangular in shape, and filled with granular proto- 

 plasm. In an hour after extrusion from the conidiophore 

 the protoplasm of the conidium became vacuolated, and the 

 conidia became rounder and larger. After this they gradually 

 turned brown, and in twenty- four hours became reddish- 

 brown, with a darker coloured central portion, and measured 

 15 to 10 ^ X 9 to 7 [X. The conidiophores measured 300 \k or 

 more in length. 



" During the above developments the submerged hyphse 

 were observed to form short branches, from which chains of 

 conidia, larger and darker in colour than the microconidia, 

 were produced. Several likely portions of mycelium were 

 fixed, and stages in the formation of these, which proved to 

 be macroconidia, were observed. Tlie short clavate hyphse 

 soon showed the formation of a clear band near the apex, 

 whiph divided off the protoplasm of the globose end from the 

 remainder. Five minutes later the cell wall at the apex of 

 the hypha disappeared, and a spherical mass of granular 

 protoplasm was extruded. A distinct cell wall was evident 

 forty minutes after, and the protoplasm was now more coarsely 

 granular and showed vacuolation. After this more conidia 

 were formed in basipetal succession in a chain. Their proto- 

 plasm became vacuolated, and the walls gradually darkened. 

 When first extruded the protoplasm is finely granular, about 

 thirty minutes afterwards several small vacuoles appear, which 

 gradually approach the centre and coalesce. After the forma- 

 tion of the central vacuole the wall begins to darken, and in 



