164 J. COSSAR EWART. 



compared to an entangled skein of white silk, and when 

 this is the case beautiful rope works (Plate XI, fig. 23), 

 made up of from two to four regularly twisted loops, radiate 

 for a considerable distance from the edges of the prepara- 

 tion. Still more beautiful are these silken ropes when the 

 threads of which they are composed are studded at irregular 

 intervals with bright refractive oval spores. 



The filaments when first formed are perfectly hyaline 

 (Plate XI, fig. 8), but soon the central protoplasmic contents 

 can be distinguished from the gelatinous looking sheath. 

 The protoplasm next divides into numerous short pieces 

 (Plate XI, fig. 9), each being about the size of the original 

 rod out of which the filament was formed. These contract, 

 leaving clear, apparently empty spaces between them, and 

 often again divide to form still shorter masses of protoplasm 

 (Plate XI, fig. 10). 



At each side of this transverse line of division minute 

 clear specks appear — the first indication of the spores 

 (Plate XI, fig. 11). These gradually increase in size and in 

 brightness, and as they increase the protoplasm disappears, 

 in fact, the spores seem to be developed out of the pro- 

 toplasm (Plate XI, fig. 12). This process seems to corre- 

 spond with the formation of chlamydospores in mucor. 

 The spores thus formed have a regular arrangement, except 

 when only one spore is formed out of the original long piece 

 of protoplasm. Soon after the appearance of the spores the 

 filaments seem to be made up of numerous segments (Plate 

 XI, fig. 12), each segment containing one spore, the spores 

 lying at the adjacent ends of the segments. Then one 

 of several changes may follow. In the first place, the 

 gelatinous-looking envelopes which now surround the 

 spores may so swell that the filament gives way, thus 

 allowing the spores to escape (Plate XI, fig. 15). Again, the 

 filament may break up into long and short pieces, the 

 spores for some time remaining in the detached segments 

 (Plate XI, fig. 16), or the filaments may remain entire, retain- 

 ing all the spores in 5?Y«^ (Plate XI, fig. 14). Whatever happens 

 the filament as it disintegrates gets first granular (Plate XI, 

 fig. 13), and then almost entirely disappears. While in a 

 granular condition minute clear spots are visible at the 

 points recently occupied by the spores (Plate XI, fig. 15). 



When the filaments break up into short segments, in 

 many cases containing a spore at one end (Plate XI, fig. 16), 

 they may be easily mistaken for germinating spores. Young 

 rods, however, as long as the remains of the spore are 

 visible in them, are rounded at both ends ; whereas pieces 



