260 THE MYXOMYCETES 



sporangium wall; spores pinkish yellow in mass, pale yellow by 

 transmitted light, closely and minutely spinulose, 6-8 fx. 



Specimens not seen, but related to Ophiotheca vermicularis by the 

 character of the sporangium wall and clearly belonging in Ophiotheca 

 if that genus is to be maintained. 



Rare. Known only from Java and Ceylon. 



7. Pericilena pulcherrima Petck 



Ann. R. Bot. Gard. Perad. 4 : 305. 1909. 



Sporangia scattered and stalked, or clustered and almost sessile on 

 an irregular hypothallus, globose, 0.5 mm. in diameter, glossy purple- 

 red or purple-brown; sporangium wall of two closely adhering layers, 

 the outer rather stout, purplish red, the inner hyaline; dehiscence 

 irregular; stalks 0.1-0.3 mm. high, red-brown, furrowed, containing 

 refuse matter; capillitium a loose network of reddish brown threads, 

 marked with warts and spines, 3-4 n in diameter, with few rounded 

 free ends and few attachments to the sporangial walls; spores reddish 

 brown in mass, paler by transmitted light, spinulose, 15—17 /x in 

 diameter. 



In spite of the tendency to form separate sporangia, the irregular 

 dehiscence and spiny capillitium would seem to ally this species with 

 Ophiotheca rather than with Perichaena. 



Rare. Known only from Ceylon. 



Family ARCYRIACE^ 



Sporangiate, rarely plasmodiocarpous ; sessile or stalked; capillitium 

 of hollow tubes, united into a network and attached below; threads 

 marked with spines, warts, cogs or rings, but not spirals. 



KEY TO THE GENERA OF THE ARCYRIACE^ 



a. Sessile or plasmodiocarpous; capillitium flaccid, bearing com- 

 plete rings 4. Comuvia 



a. Sporangiate, stalked or sessile; capillitium not marked with 



rings b 



b. Capillitium not elastic; peridium persistent 1. Lachnobolus 



b. Capillitium elastic; peridium not persistent c 



c. Capillitium without hamate branches 2. Arcyria 



c. Capillitium with hamate branches 3. Heterotrichia 



1. Lachnobolus Fr. 



Fl. Scand. 356. 1835. 



Sporangia distinct, often crowded; wall single, membranous, fuga- 

 cious above, persistent below as an irregular, shallow cup; capillitium 



