COPRINUS STERQUILINUS 209 



half, but the exact duration of the dividing period cannot be 

 given owing to the impossibihty of watching one and the same 

 basidium continuously as it undergoes its development. It was 

 found that, after a transverse section of a gill had been immersed 

 in water, the nuclei of the basidia failed to undergo any further 

 changes and that in the course of an hour or two the basidia lost 

 their vitality. The basidia became flattened at their ends and 

 showed the first traces of sterigmata just after the second nuclear 

 bipartition (/ and g). The nuclear changes observed in the long 

 basidia repeated themselves in the short basidia. Several short 

 basidia were found to be in the binucleate stage at a time when the 

 adjacent long basidia were in the quadrinucleate stage and, in general, 

 it was observed that the nuclear changes of the short basidia lagged 

 behind those of the long basidia. As soon as the sterigmata became 

 developed, it was found impossible to detect any nuclei whatever 

 in any of the basidia. 



Various forms of the hymenial elements, as seen at successive 

 intervals of time, are shown in Fig. 90. The sketch A was made 

 at 10 P.M., the sketch B at 1 a.m., and the sketch C at 2.30 a.m., 

 whilst the sketch D represents the condition of the hymenium at 

 about 12 midnight. If therefore we take 5 p.m., at which time the 

 sketch reproduced in Fig. 89, A (p. 208) was made, as the zero of a 

 time-scale, then the sketch A in Fig. 90 represents a stage of develop- 

 ment after an interval of 5 hours, sketch B a stage after 8 hours, 

 sketch C a stage after 9 • 5 hours, and sketch D a stage after about 

 31 hours. 



If the sketches A, B, and C in Fig. 90 are carefully observed, it 

 will be noticed that in each of them the long basidia are somewhat 

 further advanced in their development than the short basidia : for 

 in A the long basidia have their sterigmata developed before these 

 structures have begun to appear upon the short basidia ; in B the 

 long basidia have already commenced to develop spores, whilst 

 the short basidia as yet merely possess sterigmata ; and in C the 

 spores of the long basidia are half-grown, whilst those of the short 

 basidia are nothing more than minute rudiments. In D, which re- 

 presents the appearance of the hymenium just prior to the discharge 



of the spores, the spores of the long and the short basidia are equally 

 VOL. III. r 



