﻿the present study has been the origin and development of the 

 lamellae. In the earliest stages examined the fundament of the 

 pileus was distinctly organized, especially the marginal and lower 

 portion. It is organized within the zone of radiating hyphae 

 characteristic of many species of Coprinus which have been 

 studied. The zone of radial hyphae external to the pileus is 

 broad. It forms the blematogen, and is not separated as a distinct 

 free volva or teleoblem, since it remains concrete with the surface 

 of the pileus. The relation of the pileus and blematogen is very 

 well shown in figs. 26, 27, and 38. 



The general, annular, prelamellar cavity.— In contrast to 

 the pronounced and distinct annular gill cavity in C. comatus, the 

 annular cavity in C. atramentarius is weak, often very weakly 

 formed, but it was, nevertheless, present in all specimens examined. 

 Since it is formed as a result of the tensions caused by difference in 

 the rate of growth of the pileus, stem, and adjacent tissue, as 

 described for C. comatus, Agaricus campestris. etc., the tissue 

 underneath the pileus fundament and surrounding the stem is 

 torn apart. Since the cleavage, as already described for C. 

 comatus, A. campestris, etc., is not an even one, the tissue is 

 ''shredded" more or less, so that free ends of hyphae project into 

 the cavity from below and above. But since the cavity is here 

 a weak one, there are scattered hyphae which have not become 

 severed, but extend across the cavity from above downward or 

 vice versa. 



The palisade layer of hyphae.— The palisade layer of 

 hyphae is present at this time, or even earlier, but the hyphae at 

 first are slender. In the development of the pileus within the 

 system of radiating threads, the hyphae on the margin and on the 

 under surface which form the fundament of the hymenophore are 

 parallel and rather closely compacted, so that the young fundament 

 of the hymenophore has a palisade structure even before the tearing 

 apart or shredding of the fundamental plectenchyma below, into 

 which the hymenophore is progressing by growth. This funda- 

 ment of the hymenophore stains more deeply than the funda- 

 mental plectenchyma below, or the pileus above, or the enveloping 

 blematogen (figs. 26-35). 



