252 PROCEEDINGS OF THE AMERICAN ACADEMY. 



colorless or opalescent with a comparatively thick wall and look 

 much like chlamydospores. The adjacent cells of the filament on 

 either side of them become stimulated and also enlarge to some 

 extent, but remain colorless longer than the others, although they are 

 eventually incorporated into the bulbil. The primordial cell or cells 

 soon become brownish and produce others by gemmation, which in 

 turn produce still others (Figures 2-5, Plate 2), so that the mature 

 bulbil finally consists of one or two, occasionally more, large central 

 cells with slightly thickened walls, surrounded by a number of smaller 

 less highly colored ones, with thinner walls. The mature bulbils 

 measure from 50-60 m in diameter, although they may vary consider- 

 ably. 



Sometimes three or four intercalary cells enlarge and take part in 

 this process, producing an elongated, somewhat irregular bulbil, 

 while at other times there are as many as eight or ten such cells; 

 but in this latter ease they seldom go farther than the production of 

 a few lateral cells which soon become empty and colorless, as is 

 shown in Figure 7, Plate 2. 



Not infrequently the terminal cell or series of terminal cells becomes 

 the primordium (Figures 24-25), the further development of which 

 is the same as the one already described. In Van Tieghem cell- 

 cultures, bulbils are sometimes produced with more central cells than 

 ordinarily occur in tube-cultures, and these, which are usually spheri- 

 cal, contain oil globules which give them a peculiar, somewhat 

 opalescent appearance. The cortical cells in such cases are somewhat 

 flattened, as indicated in Figure 22, Plate 2, a condition which may 

 be due to the pressure exerted by the increased number of the central 

 cells. 



The perithecium. — The form of the primordium of the perithecium 

 is essentially the same as that of the bulbil but the former, as has 

 already been stated, can, even in the early stages of its formation, be 

 readily distinguished from the latter by the fact that it is colorless. 

 It can be distinguished also from the primordium of the perithecium 

 of M. ccrvicula, which in many respects it resembles, by the fact that 

 the latter turns brownish at a much earlier stage in its development, 

 producing a large number of radiating hyphae, so that its outline is 

 soon indistinguishable. 



Usually one, rarely two, intercalary cells take part in its formation, 

 and from these, two or three large cells are produced laterally by 

 budding (Figure 8, Plate 2). From the intercalary cells, or, more 

 frequently, from the adjacent ones of the hypha, branches are sent 



