70 



A Monograph of the Myxogastres. 



from the earliest condition. In Lamproderma molaceum the 

 columella is filled with large spherical, or 1 from mutual pressure, 

 polyhedral cells, a character repeated in the stem of several 

 species of Arcyria. The three genera Amaurochaete, Brefeldia, 

 and Eeticularia are only known in the aethalioid condition, and 

 superficially appear quite isolated from the remaining genera, 

 but structurally are nothing more than confluent forms of such 

 genera as Stemonitis and Lamproderma. Comatricha confluens 

 is a connecting link between the two extremes. According to 

 the preconceived idea that the presence of a columella is of 

 sectional importance, the genus Siplwptychium belongs to the 

 present division, nevertheless its affinity with the Peritricheae 

 is obvious. 



The following arrangement indicates the affinities of the 

 genera included in the Columellifcrae, and the points of contact 

 with other sections. 



STEMONITIS. A ncyroplwrus. 



BREFELDIA. Rostajituskia. 



AMAUROCHAETE. 

 RETICULARIA. 



LAMPRODERMA.- 



I 

 Echiiwstelium. 



I 

 Orthoiricha. 



Raciborskia. 



w 



K " 



-B pq 



f**^ 



O 



H 

 i i 



3 



Siph optychiiim . 

 TUBULIXA. 



PERITRICHEAE. 



