35 



other species of the genus have other pronounced characters. 

 They require close microscopical study in order to make proper 

 determinations. 



Genus 10. COMATRICHA 



The genus is closely related to Stemonitis and differs ma- 

 terially only in the absence of the surface net to the capillitium. 

 However, this is not a sharp line of demarcation as certain 

 species of Comatricha have a partially developed net, and some 

 species of Stemonitis have an imperfectly developed one. The 

 same general conditions and brownish colors prevail, and in 

 addition in Comatricha we have globose sporangia; a greater 

 tendency to form a more persistent peridium and a columella 

 that in some species divides into branches instead of continuing 

 to the top. A number of species are quite common but it would 

 take too much space to describe them all. C. nigra has globose 

 sporangia with a dense capillitium, and a columella that extends 

 to the top. If the columella divides into several branches it is 

 C. elegans. Both species have long stalks. C. typhoides has cylin- 

 drical sporangia on long or short stalks, and is often 3-4 mm. in 

 height. The stalk often has a thin, white membrane surrounding 

 it. There is also usually a gray peridium which persists for some 

 time before it peels off. The species can always be recognized 

 by the spores which have a few prominent warts, not seen in 

 any other member of the genus. 



Genus 11. ENERTHENEMA 



In this genus the black stalk and columella ends in a shining, 

 black, circular disc from which the dark capillitium hangs. The 

 common and typical species is E. papillatum, and the other two, 

 which are rare, differ little therefrom. The disc on the outside 

 distinguishes the genus from all other species of Mycetozoa. 



Plate II 

 Fig. 9. Lamproderma arcyrionema, X4 



Fig. 10. Cribraria intricata, X6 



Fig. 11. Enteridium rozeanum, X2 



Fig. 12. Lycogala epidendrum, XI 



Fig. 13. Trichia varia, X8 



Fig. 14. Arcyria denudata, X4 



Fig. 15. Arcyria nutans, X3 



Fig. 16. Cerationiyxa fruticulosa, X6 



