34 A Monograph of the Myxogastres. 



a connecting link with another order, the ColumcUifcme, where 

 the caiiillitiura originates in a totally different manner. The 

 following arrangement illustrates the evolution of the genera 

 included in the Pcritrichcac, and the points of affinity with other 

 orders — 



DiCTYDIUM. 



<d^ 



:> 



I 



Cribraria. 



Clathroptychium.- 



ft o 



-Prutodermium. 



PERITEICHEAE. 



(British genera are printed in small capitals, exotic genera in italics.) 



ANALYSIS OF THE GENERA. 



PERITEICHEAE. 

 Sub-sect. TUBULINAE. 



TUBULINA. Sporangia crowded to form an aethaUum. , 



Protodermium. Sporangia scattered. 



Sub-sect. Cribrariae. 



Orcaddla. Sporangia perforated at tlie apex. 



Enteridium. Sporangia with small lateral perforations, or 

 broken up into an irregular network. 



Clatiiroptychium, Sporangia with large symmetrical open- 

 ings in side walls, apices of sporangia permanent. 



Cribraria. Permanent portions of upper part, or whole 

 of sporangium forming an irregular network. 



DiCTYDIUM. Permanent ribs of sporangium radiating from 

 the calyculus and converging towards the apex, joined by 

 thinner transverse bars. 



