ADAMS: ORIGIN OF LAMELLAE IN SCHIZOPHYLLUM 331 
lamella was continued from its point of origin so long as the 
growth of the crenature allowed for its development. After 
attaining a certain width the crenatures gradually become nar- 
rower and thin out at the margin. Under such conditions of 
limited growth some of the enclosed lamellae in the crenature can 
no longer be continued and do not reach the margin of the crena- 
ture. In the mature carpophore the margin is always thinned 
out and the gills thus become lanceolate in form. 
DISCUSSION 
In recent years considerable advances have been made in our 
knowledge as to the origin and development of the lamellae in 
Fic B. Diagram of ventral surface of carpophore showing arrangement of 
crenatures and gills. a, primary gill; b, secondary gill; c, a disconnected secondary 
gill. 
different members of the Agaricaceae. The endogenous origin 
of the lamellae has been firmly established for a number of forms. 
In Schizophyllum the lamellae originate by the formation of 
endogeneous gill cavities in a fashion similar in principle to that 
which Levine (714) finds in Coprinus micaceus. They are de- 
veloped simultaneously in C. micaceus, while in Schizophyllum 
they are successively formed. In both cases a series of gill cavities 
are produced which represent the space between the adjacent. 
sides of a pair of lamellae. There is no general gill cavity into 
which the lamellae grow downward. In Schizophyllum, owing 
to its habit of growth, this method of origin of the gill cavities as 
