aCHIZOMTGETES. 211 



gium without net-like thickeuings, now and then symmetrically per- 

 forated. 



Licea and Tubulina are genera of this order of which we have 

 species. 



Order V. Heterodermese. Sporangia witliout capillitium, colu- 

 mella, or lime ; wall of sporangium delicate, when mature at least partly 

 cracked, exposing the net-lilie flat thickenings of the inner side of wall ; 

 spores and thickenings of the inner wall in one and the same sporau- 

 gium usually of uniform color. 



Dietydium and Cribraria are our common genera. 



Order VI. Columelliferse. Spores, capillitium, and columella 

 uniformly bright-colored, without lime; capillitium of very thin-eided 

 tubes, witliout thickenings, combined into a thickly intricate but loose- 

 hanging net. 



Represented by the genus Seiicularia. 



Order VII. Calonemese. Wallsof sporangia, spores, and capillitium 

 usually uniformly colored in the same sporangium. Color variable 

 from yellow to brownish or chestnut ; more rarely olive green or gray- 

 ish while ; capillitium usually strongly developed ; threads simple, or 

 combined into a net, either entirely free or grown to certain places of 

 the wall of the sporangium ; walls of the threads very rarely smooth, 

 usually provided externally with protruding thickenings, either spiral- 

 shaped or under the form of numerous spines, warts, or transverse 

 rings; without fixed columella; exceptionally containing lime, exclu- 

 sively on the walls of the sporangia; now and then sethalia covered 

 with a stout double cortex of colored cells. 



Arcyria and Trichia are our common genera. 



(i) Specimens of the Slime Moulds may be obtained for study by ex- 

 amining the surfaces of decayed loirs, and the barl;-covered ground in 

 tan-yards. They may frequently be found on decaying leaves, and 

 occasionally on the grass and mosses near decaying vegetable matter. 



§ II. Class Schizomyoetes. 



277. — These are minute unicellular Protophytes, which 

 reproduce by simple transverse fission. The cells are gener- 

 ally somewhat elongated, often much so, although in one 

 family they are spherical ; they are sometimes provided with 

 cilia, by means of which they move rapidly through the 



paper entitled " The Myxomycetes of the United States," published in 

 the Annals of the Lyceum of Natural History of New York, Vol. XI., 

 1877, the same author enumerates our species according to Rostafinski's 

 arrangement, and gives a copious list of synonyms. 



