330 SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
two gill cavities which originate endogenously as tubes in the 
substance of the carpophore. 
The tissue above the gill cavities already formed increases by 
intercalary growth and in general the gill cavities lie much nearer 
the ventral than the dorsal surface of the carpophore. The tissue 
below the gill cavity appears gradually to become looser in texture 
as the gill cavity gets larger and this favors the splitting by which 
the edges of the gills are set free. 
Owing to the method of their origin the margins of the lamellae 
are never entire, but appear irregular and frayed out. The final 
splitting of the lamella is apparently a hygroscopic phenomenon 
as described by Buller og). The trama is continuous with the 
tissue of the pileus above the gill. In transverse sections of the 
lamellae the split is seen to be parallel with the elongated hyphae 
of the trama, as seen in PLATE I, FIGURE 7. 
FURTHER DEVELOPMENT OF THE CARPOPHORE 
The growth of the carpophore is marginal and the lamellae 
are extended in length by the elongation of the gill cavities and the 
palisade layer in the interior pari passu with the development of 
the carpophore. 
In the young immature carpophores after several lamellae 
have been formed the margin becomes divided into the crenatures. 
These crenatures are due to the development of a cleavage lamella 
splitting in certain cases clear through the dorsal surface of a pileus 
(rExT-FiG. А, NO. 4). They not only include the primary gills but 
allow for the origin of new gills on either side in the usual way. 
The later-formed lamellae are narrower and thus we get the lamellar 
systems of Fries and the fasciculi of gills of Buller. The pileus 
enlarges by the continued growth of the primary lamellae and the 
successive development of additional lamellae, all of which have | 
their origin from gill cavities in the manner described. The more 
central crenatures are the oldest and the younger are towards 
the sides of the pileus. 
In mature carpophores it is often observed that a short gill 
appears isolated between the right and left halves of the adjacent 
lamellae (тЕхт-ғіс. B, c). At the point where such a lamella 
originated the crenature was increasing in width. The new 
