BUTLER. 263 



bore sporangia and conidia on the extra- ma trical part of the cul- 

 ture and oospores within the tissues of the ant. 



From an examination of these the fungus proved to be the 

 well-known Pythium de Baryanum. Subsequent ant cultures gave 

 oospores also on the extra-matrical mycelium. The fungus grew 

 well on boiled Ricinus seeds but on this substratum few sporangia 

 were formed, oospores being very numerous within and outside 

 the tissues. Seedlings of garden cress (Lepidiitm sativum), which 

 is well known to be subject to damping off, were attacked in charac- 

 teristic fashion when grown in soil containing the fungus. The 

 reproductive bodies produced in this substratum were chiefly 

 oospores, which were developed both intra- and extra-matrically. 

 The failure of several observers to obtain the sporangia of this spe- 

 cies is possibly to be attributed to the cultures having been made 

 on plant tissues only ; sporangia appear to be rarely produced under 

 such circumstances, whereas on animal tissues they are formed in 

 great abundance. 



The mycelium is composed of much branched hyphae, the main 

 strands being up to 4 or om . in diameter, the lateral ramifications 

 much finer (PL V, Fig. 8). Irregular swellings, such as are formed in 

 several other members of the genus, are not common, the hyphse 

 tapering regularly as a rule. Within the tissues, septa are infre- 

 quent, except in the older stages, but the aquatic mycelium is richly 

 septate, especially as soon as the hyphal contents begin to be used 

 up in the formation of the reproductive bodies (Fig. 9). 



Sporangia are found in large numbers on the second day in ant- 

 cultures. They are terminal or intercalar, the former being mostlv 

 spherical, the latter elliptical or irregular (Figs. 8 and 10). The 

 hypha near a sporangium is frequently emptied of its contents, the 

 empty part being sometimes cut off from the full by a septum. 

 Germination in undisturbed cultures generally occurs while the 

 sporangium is still attached to the mycelium. A very prominent 

 beak is formed, generally laterally and about equal to the diameter 

 of the sporangium in length. The sides of this beak are not usu- 

 ally as straight as is figured by Hesse. A single large vacuole is 



