ADAMS: ORIGIN OF LAMELLAE IN SCHIZOPHYLLUM 329 
trama of the matured lamellae. It was observed several times 
that the inner surface of the gill cavity before maturity was not 
completely covered by the palisade layer. This condition is found 
usually along the lower edge of the gill cavity, but the condition 
becomes normal with the maturity of the gill cavity (PL. 1, FIG. 4). 
The wall between two adjacent gill cavities is occasionally quite 
weakly developed owing to the close proximity in their origin. 
Dk 
КЕС? 
4 
A. дааа of sections illustrating different stages of development of 
e carpophore. т. Transverse vertical section of a button in which no 
ME has appear ie . Section cut as above showing later stage with four 
endogenous and separate Pid cavities, the penis ones ие 3. А longitudinal 
median section through a y ph eral gill cavities which 
have opened longitudinally а. a, Region Ру extension of the hymenium ргі- 
mordium. 4. Transverse vertical sections through the apical growing region of the 
carpophore, showing the origin of the crenatures, two of which are already separated 
by clefts extending to the dorsal surface of the carpophore. The middle and outer 
crenatures at right show gill cavities comparable to those in Fig. 4, Pl. т. In the 
case of the others, similar gill cavities appear in sections nearer the base of the 
pileus. 5. Transverse vertical section like those of Buller through the median 
Portions of a carpophore, showing a series of young lamellae, the gill cavities open 
below except in the case of the one at the right. The gills already show more or 
less of the characteristic splitting. 
In such instances the separating wall, which would normally 
become a lamella, gradually thins out and disappears. Instead 
of two gill cavities normally maturing they become one by the 
abortion of the separating wall. 
THE LAMELLAE 
The gill cavities split along their lower edge and lamellae are 
thus completed. They consist, as noted, of the adjacent walls of 
