](i ART. 14.— K. YEXDO: 



lateral walls and the non-zonal arrangement of the cells are similar to 

 those of the latter species. 



The above mentioned genicula are all those in the normal position. 

 The characters are more or less constant to the species. In the 

 abnormal genicula, as it were, these descriptions may not be often 

 sharply applied. 



The greater part of this chapter does not hold good in the fronds 

 of Amp. aspergillum. In this species an articulus is built up of two 

 and only two zones of the periclinal cells, covered with a few layers 

 of cortical cells. The lower of the two zones practically fills up the 

 entire portion of the medulla. The cells constructing it are much- 

 elongated filaments of nearly equal length, running longitudinally in 

 an exact sense. The upper zone is a layer of elliptical cells, each of 

 which is situated at the top of the filamentous cell. These elliptical 

 cells have their longer axis in the same direction as the filamentous 

 cells below them, but those at the peripheral region bend horizontally 

 by degrees and finally become confluent with the cells of the 

 innermost cortical layer. Hence in the longitudinal sections of an 

 articulus we have a Q-shaped layer of minute cells holding the bundle 

 of the filamentous cells wholly inside of it. The boundary of the 

 neighbouring articuli lies at the points where the basal extremities of 

 the filamentous cells of an articulus come into contact with the 

 terminal extremities of the elliptical cells of the lower articulus. The 

 slit between the articuli which suggests a linear geniculum in the 

 external appearance of a frond, is around this region (fig. 7). 



We have several reasons for believin«; that the lower half of the 

 filamentous cells serves as the genicular portion proper of the other 

 species. In the preparations the cortex around this portion seems to 

 be entirely free from continuation with the filamentous cells like a 

 circumgenicular cortex of other species. But it would be a little 



