THE PROTEOMYXA 



ii 



monas. Zoospores with one or two flagella have been seen in all the 

 genera except Myxodictyum, Bursulla, and Tetramyxa. It is possible that 

 Colpodella is related to the Mastigophora. 



(III.) Protomyxa (Fig. 6, 1) was found by Haeckel attached to the shells 

 of Spirula on the coast of the Canary Islands, in the form of orange-yellow 

 flakes consisting of branching and reticular protoplasm nourishing itself 

 by the ingestion of Diatoms and 

 Peridiniae. This is a plasmodium 

 formed by the union of several 

 amoebulae. The plasmodium en- 

 cysts and gives rise to numerous 

 flagellulae or swarm-spores. The 

 diameter of the cyst is '12-'2 mm. 

 The flagellulae pass into an anaoe- 

 bula phase, and the amoebulae 

 unite to form the plasmodium. 



Myxodictyum, Haeckel, consists 

 of a number of protomyxa-like 

 individuals united by their pseudo- 

 podia to form colonies. It is 

 pelagic in habit and was found by 

 Haeckel at Algeciras in Spain. 

 Marine. 



(II.) Gymnococcus, Zopf, occurs 

 mCladophora, Diatoms, and Cylindro- 

 spermum. It forms a plasmodium. 

 When fully fed it gives rise to zoo- 

 cysts, from which three to twelve 

 biflagellate zoospores escape. 



(II.) Aphelidium, Zopf, lives in 



the cells of Coleochaeta and in macerations of plant tissues. Hypnocysts 

 furnished with an operculum are formed. A nucleated zoospore with 

 one flagellum has been found in A. lacerans (de Bruyne). 



(II.) Protomonas, Cienkowski, has biflagellate zoospores which become 

 amoeboid and unite to form a plasmodium. Freshwater and marine. 



(II.) Colpodella, Cienkowski (Fig. 8, A), is possibly allied to Protomonas. 

 The zoospores have only one flagellum, and attack Mastigophora before 

 they become amoeboid. They do not, however, form plasmodia. 



(II.) Tetramyxa, Gobel, forms large galls on various water-plants, 

 especially Ruppia. 



(II.) Plasmodiophora, Woronin, is the cause of the disease of turnips 

 known as "Fingers and Toes," or " Hanburies " (German, Herniekrank- 

 heit). The spores are found in damp ground. Each spore gives rise to 

 a minute nucleated amoeboid zoospore with a single flagellum. This 

 penetrates into the cells of the root and loses its flagellum. It increases 

 in size and the nuclei divide. After a time plasmodium-formation begins 

 by the fusion of neighbouring amoebulae, and the tissues of the host-plant 

 disintegrate. As soon as the plasmodium is formed the nuclei increase 

 rapidly by karyokinesis, but according to Nawaschin (21) there is a period 



Boderia turneri. 



(After Wright.) 



