290 PKOCEEDINGS OF THE AMERICAN ACADEMY. 



sections show that the bulbil is uniform throughout (Figure 20, Plate 

 7) all the cells containing protoplasm, and under favorable conditions 

 capable of sending out germ tubes. In this respect it differs from the 

 typical sclerotium, which usually has a compact layer of several cells 

 in thickness (the rind) which forms the margin. The primordia are 

 colorless at first (Figures 2-4, Plate 7), then light-yellow, later ruby- 

 red, and finally reddish brown and opaque. 



In this as in most other bulbils the process of development may 

 vary greatly. Figure 1, Plate 7, shows the primordia of three bul- 

 bils, two of which and possibly the third also, would prol)ably have 

 grown together, forming a large, irregular, sclerotium-like body. 

 This phenomenon occurs quite frequently, giving rise to a variety of 

 forms, which \avy with the number of the initial primordia taking 

 part in their development, their proximity, and the inequality of 

 their development. In such cases each primordium develops in- 

 dependently, until its lateral branches intertwine with those of one 

 or more that lie adjacent to it, a compound bulbil finally resulting, 

 in which the several origins are indistinguishable. 



Aspergillus-liL-e fructification. Conidia are frequently produced 

 both on Aspergillus-like heads and also laterally, on the sides of the 

 hyphae (Figures 10-11, Plate 7). The latter are usually isolated, 

 sometimes irregularly grouped. The conidiophores arise from erect 

 lateral branches, and are frequently septate; rarely branched. They 

 are very minute, so that one can detect them only with difficulty, 

 even with a good hand lens. The length of the conidiophore varies 

 greatly, some being quite short, others so long that it is difficult to 

 trace tliem to their origin. The swollen head of the conidiophore is 

 usually spherical, or nearly so, and on it are arranged somewhat 

 irregularly numerous simple sterigmata. These vary slightly in size 

 and shape, but always have a broad base and taper more or less 

 gradually, often to a point, at the distal end. The relative length of 

 the vertical and transverse diameters of the swollen base varies some- 

 what, so that one may find gradations in shape from almost spheri- 

 cal to napiform. The conidia are nearly spherical, sometimes ovoid, 

 smooth, colorless, minute, occurring in chains, and dropping off very 

 readily; but in moist atmosphere the conidia, instead of being pro- 

 duced in a chain, frequently adhere and form clusters much like those 

 of Hyalopus. 



There are many variations in the arrangement of these conidia, 

 which may, for example, arise, as is shown in Figure 9, Plate 7, termi- 

 nally and laterally on irregularly clavate extremities of hyphae. 



