1914] THAXTER—NEW ZYGOMYCETES 355 



being characteristically corrugated through the presence of suc- 

 cessive constrictions, the ultimate divisions bearing the sporangio- 

 liferous heads. From the whole surface of the latter buds arise, 

 distributed without great regularity, which as they develop become 

 distinguished into two parts: a short stout basal stalk which 

 later assumes the form of a nearly spherical vesicle, and a terminal 

 rounded portion which becomes transformed into the broadly 

 elliptical sporangiolum (figs. 3 and 4). In each sporangiolum three 

 spores are normally produced by longitudinal radiate cleavage, but 

 even in typical sporangiola instances occur in which one or all of 

 these spores may divide before maturing, so that there may be four 

 to six in the mature sporangiolum (figs. 5 and 7). In such cases 

 the spores are more irregular in form, size, and arrangement. When 

 fully mature, each sporangium becomes separated from its vesicle 

 (fig. 6); or, if not quite matured, may be separated with the 

 vesicle coherent, as in figs. 5 and 7. Ordinarily the vesicles are 

 left attached to the sporangioliferous heads as is shown in figs. 2 

 and 3. The normal spores' (fig. 9) are somewhat bean-shaped 

 at first, tending to assume a more rounded form after they are 

 freed from the sporangiolum, rather rich purplish brown in color, 

 marked by longitudinal depressions which appear as fine dark lines, 

 more or less parallel and slightly labyrinthine, which, when the 

 spores are freshly discharged in water, are sufficiently conspicuous, 

 although they become faint after swelling or mounting in glycerine. 

 When viewed end on, as in fig. 8, the furrows give the margin a 

 finely corrugated outline. From either pole in all the spores a 

 variable number of very fine and hardly visible, irregularly divergent 

 appendages radiate, which seem to be formed from an intersporal 

 substance and converge to a more or less distinct cap or small mass 

 of viscous material, which sometimes forms a distinct dark spot. 

 These appendages are straight and very fine, seldom much longer 

 than the spore, and are readily seen only in freshly separated spores 

 and with considerable magnification. They seem to be entirely 

 similar to the corresponding structures which are found on the 

 sporangiospores of Choanephora. The spores germinate rapidly in 

 nutrients by producing a terminal or lateral germ-tube which 

 grows directly to a mycelium. 



