The Origin and Development of the Apotheeium etc. 
387 
the terminal cell which later disintegrate and take no fnrther part in 
the development of the fruit body. 
In order to trace the long terminal cell as well as to reconstruct 
the coils of the carpogone, serial sections are absolutely nccessary. But 
even then difficulties abound. I have notcd above tliat several carpogones 
frequently originate dose together. The coils offen become entangled 
so tliat in a section ten microns thick it is impossible to follow any one 
carpogone for more than a few cells and cpiite a hopeless task to recon- 
struct any one. In order to facilitate the tracing of these hyphae, I have 
eilt many sections 25 microns thick. With some practice, these thick 
sections may be well stained for cytological as well as for morphological 
study. In such a section offen as many as two consecutive coils of a carpo- 
gone may be found with no break (Fig. 25, PI. XXXII). But tliis depends 
entirely on the looseness or regularity of the coil. However, the terminal 
j cell always extends through several sections. The carpogone which is 
i shown in Figure 36, PI. XXXIII, was rec.onstructed from 13 sections. For 
this work of reconstruction I have found it necessary to make camera 
lucida outlines of the thallus under low power magnification and then 
to indicate on those clrawings the points at which the hypha in question 
begins and ends. I have then located these points with the oil immersion 
lens and taken micrometer measurements of the distances between neigh- 
boring hyphae. The next section is then outlined, the points located 
and the measurements compared. In this way it is possible to trace 
with considerable accuracy a carpogone which is not too much entangled 
with others. Tracing the terminal cell from section to section, one finds 
tliat it grows not vertically upward toward the surface of the thallus, but 
more or less horizontally or parallel to the plane of the thallus. It is not 
straight, but often somewhat winding. It contains very little stainable 
cytoplasm, which is usually in irregulär shreds or plates and slightly 
granulär. The nucleus has enlarged with the growtli of the cell and is usu- 
ally somewhere near its middle part. The nucleus is oval or sometimes 
more elongated (Fig. 54, PI. XXXV). The chromatin is on the nuclear 
membrane, and frequently granules which stain like chromatin appear 
to be just outside the membrane in the cytoplasm. Tliere is often a 
granule at one end of the nucleus which because of its position and stain- 
ing capacity suggests a centrosome. The end of the nucleus bearing 
this body may be turned either toward or aAvay from the apical end of 
the cell (Fig. 54 a and b). In Figure 54, the nucleus at a is quite near 
the end of the cell ; but this is exceptional. The nucleus of the penultimatc 
cell of the trichogyne is also sometimes elongated. 
26 * 
