278 PROCEEDINGS OF THE AMERICAN ACADEMY. 



primordia form eventually quite close coils. The helix which consists 

 of one to one and one-halt' turns, divides into cells from which short 

 lateral branches are produced, usually growing towards the center, 

 rarely outward (Figures 5-7, Plate 9). These branches twine and 

 intertwine, the lateral walls adhering firmly so that eventually a 

 somewhat spherical body is formed which superficially resembles the 

 sporangium of a fern. The cells of the original spiral arc more promi- 

 nent than the others, usually slightly elevated with well marked walls, 

 and correspond to the annulus, as will be seen from Figures 9-10, 

 Plate 9. Figure 10 is a view of an immature bulbil, looking down 

 on the "annulus," while Figure 9 is a side view of the same. At 

 maturity the bulbil, which is nearly spherical, is 55-88 n in diameter. 

 The cells of the primary coil usually become empty and lighter 

 colored, showing slight thickenings scattered over their surface, oc- 

 casionally projecting slightly, thus giving the appearance of minute 

 spines. 



Sometimes a lateral hypha divides dichotomously and each branch 

 coils up and produces a bulbil. Similar branches may be produced 

 directly from the superficial cells of a bulbil (Figure S, Plate 9). The 

 mode of development in this form resembles that of certain species of 

 Urocystis, such as U. cepulae, the common onion smut, in which a 

 lateral branch coils up, making about one turn, and this divides 

 into cells from which secondary branches are given off. Figures 4, 

 5, 6 and even 7, Plate 9, might almost equally well illustrate the 

 development of Urocystis cepulae. 



Papulospora coprophila, nov. comb. 



Helicosporangium coprophihtm Zukal ('96). 



Plate 10, Figures 1-10. 



Mycelium white, a septate, floeculent, abundant, persistent; bulbils, 

 dark brown, more or less spherical, 30—10 n (rarely 00 n) in diameter, 

 with one to four (sometimes as many as 10) large central cells sur- 

 rounded by a cortex of empty colorless or slightly brownish ones; 

 primordium spiral, of one to four turns, the end cell usually becoming 

 a central cell. Conidia on bottle shaped sterigmata, frequently in 

 white tufts scattered over the surface of the substratum. 



On onions, straw, horse dung, etc., Cambridge, Massachusetts, 

 and California. 



Onions have proved very productive as a substratum for bulbils. 

 Some onions obtained from the Boston market which had been shipped 



