PROTEOMYXA. 



917 



and becomes irregular in shape ; it gives off lobose processes while the radiant 

 pseudopodia are confined to a few spots. Ingestion of Bacteria was observed. 

 The colonies thus produced appear to grow till food is scarce, and then to break 

 up. Each chlorophyl body carries away with it a portion of protoplasm. Large 

 encysted individuals occur ; the cyst membrane is resistent. The chlorophyl may 

 be disseminated through the encysted mass. The two remaining Heliozoon-like 

 genera are also both non-nucleate, but are characterised by the fact that they form 

 colonies. Monobia confluens lives in freshwater, and perhaps damp earth ; its 

 pseudopodia are radiant with minute varicosities. It multiplies by fission, and the 

 two individuals thus formed may remain united by a bridge of protoplasm. Union 

 may take place also by the pseudopodia. Myxodyctium sotiale is marine; the 

 colony is formed by the union of the branching and anastomosing pseudopodia. 



Monadineat. Forms typically characterised by having two kinds of cysts, a 

 zoocyst in which the organism undergoes division into spores either fiagellulae or 

 amoebulae, a sporocyst in which it becomes a resting-spore or chlamydospore. 

 Zopf makes two subdivisions, M. zoosporeae and M. azoosporeae *. 



M. zoosporeae. The zoocyst gives origin \,Q fiagellulae s. zoospores. There are 

 three families. 



The first, Pseudosporeae, is characterised by the fact that the chlamydospore is 

 formed in a sporocyst. There are four genera. Colpodella pugnax is sickle-shaped, 

 with a single cilium, nucleus and contractile vacuole. It perforates the membrane 

 of the green Flagellate Chlamydomonas pulvisculus and sucks out its contents. 

 Next it comes to rest, becomes globular, forms a double membrane, an outer thick, 

 and an inner thin ; then segments into a number of zoospores which are set free by 

 the bursting of the thick membrane, the protrusion and gelatinisation of the thin. 

 When it passes into a chlamydospore it becomes globular, secretes a membrane 

 and then contracts into a small globular or ellipsoidal body. The genus Pseudospora 

 differs from Colpodella in that the zoospore passes into an Actinophrys-\fa& Amoeba. 

 Ps. aculeata is parasitic in the cells of the algal Oedogonium ; Ps. parasitica in those 

 of Spyrogyra ; Ps. Bacillariacearum in Diatoms ; Ps. maligna in the protonemata 

 of the Moss Hypnum. The resting-spore is known in the two first named. The 

 ingesta are expelled within the cyst before the spore membrane is formed. Proto- 

 monas is distinguished from the foregoing by forming fusion-plasmodia. P. amyli 

 is an inhabitant of stagnant waters, and lives upon starch grains. The zoospore is 

 biciliate, the two cilia being at one or at opposite ends of the body. It passes 

 into an Actinophrys-\ks. Amoeba, which as it grows loses the power of emitting 

 pseudopodia ; it then forms a cyst and segments into zoospores. Or several spores 

 may fuse into a plasmodium round a starch grain. The plasmodium does not emit 

 pseudopodia, and finally secretes a membrane. It then segments into zoospores, 

 or before it does so, it may escape from the cyst and creep about by means of long 

 pseudopodia. The resting-spore is ellipsoidal or globular with a thick cyst which 

 has minute internal tubercles. P. Spirogyrae is parasitic in Spirogyra and Zygnema. 

 The zoospore is uni-ciliate ; it forms amoebae or plasmodia with blunt pseudopodia. 

 The resting-spore behaves like that of Pseudospora. P. Huxley i is marine, and lives 

 upon Diatoms. The genus Diplophysalis is characterised by the fact that the resting- 



1 The following epitome is made from Zopf's article in the ' Encyclopaedic der Wissenschaften,' 

 quoted infra. 



