HOTSON. — CULTURE .STUDIES OF FUNGI. 277 



frequently run into irregular sclerotium-like bodies, 250-300 ju in 

 diameter. In old cultures the hyphae often form a felted mass over 

 the substratum. This mode of development is similar to that of P. 

 ■pannosa, from which, however, it is easily distinguished by the color 

 of the mycelium and bulbils, those of the latter species being black. 

 It also resembles P. immersa, but it is lighter in color and does not 

 have such large cells with conspicuous oil globules and the bulbils 

 are not immersed in the substratum. Figures 11-17, Plate 9, illus- 

 trate the mode of development of this bulbil. 



Papulospora spinulosa, n. sp. 

 Plate 9, Figures 1-10. 



Mycelium white, scanty, septate, procumbent, becoming slightly 

 brownish when old, 3.5 /u in diameter, the old hyphae somewhat 

 larger; bulbils hyaline until well developed, at maturity light choco- 

 late-brown, somewhat spherical, 55-88 ix in diameter, 50-00 cells in 

 surface view; primordium a coiled lateral branch which remains 

 prominent throughout the development, becoming empty and show- 

 ing slight thickenings in the walls. No other means of reproduction 

 known. 



On rat dung, Kittery Point, Maine. 



This fungus was found on a gross culture of rat dung obtained from 

 Kittery Point, Maine, and has been grown for about three years on 

 various media without producing any reproductive body other than 

 bulbils. The mycelium is white and grows quite sparingly on most 

 media. It has been found that bran agar or rat dung agar is the 

 best nutriment on which this species will grow. 



The bulbils. — During their early stages of development the bulbils 

 are hyaline until they are about half grown, at which time they begin 

 to turn a light brown and at maturity assume a chocolate-brown 

 color, often covering the whole substratum with several layers, so 

 that all appearance of hyphae is lost sight of, except around the 

 margin where a white zone about 5 mm. in width indicates the 

 actively growing region of the mycelium and the formation of new 

 bulbils. In the process of development a short lateral branch coils 

 up, usually crosier fashion (Figures 1-4, Plate 9), although occasion- 

 ally the tip somewhat overlaps, as shown in Figure 3, Plate 9. The 

 primary loop varies greatly in size, as may be seen from a compari- 

 son of Figure 1 with the other figures representing the development, 

 all of which are drawn on the same scale, but even these large open 



