THE PROTEOMYXA 



seems certain that several individuals may fuse to form a plasmodium. 

 No contractile vacuoles occur at any stage. The size varies consider- 

 ably, 20-70 p.. They are nearly all freshwater forms, but one species, 

 V. gomphonematis, is also marine. 



Monadopsis, Klein, is probably a species of Vampyrella. 



(I.) Vampyrellidium, Zopf. This genus is parasitic on freshwater 

 Algae, particularly on Lingbya. Two kinds of cysts are formed, the 

 zoocysts with a clear homogeneous membrane, and the hypnocysts with a 

 thicker membrane. In other respects it is closely related to Vampyrella. A 

 nucleus surrounded by a hyaline area is said (Zopf) to occur at every stage. 



(I.) Leptophrys, Hertwig and Lesser (Fig. 3), appears to be closely 

 related to Vampyrella, but it forms larger vacuolated plasmodia by the 

 fusion of the amoeboid zoospores. It is also characterised by the presence 

 in the protoplasm of numerous paramylum granules. Like Vampyrella 

 it is found parasitic on various freshwater lower Algae. It is either 

 colourless or tinged with chlorophyll. The cysts are sometimes 0'25 mm. 

 in diameter. They give rise to three or four amoeboid zoospores. No 

 nuclei have been observed at any stage. 



(IV.) Monopodium (Haeckelina), Mereschkowsky, is an Actinophrys-like 

 form with hyaline protoplasm and very delicate radiating pseudopodia 

 attached to foreign bodies by a stalk. 0'2 mm. White Sea. Arclierina 

 (see p. 33). 



(IV.) Nuclearia, Cienkowski (Fig. 8, E), also appears to be related to 

 Vampyrella, but as a nucleus or nuclei and contractile vacuoles have been 

 observed by several authors, it is perhaps more natural to regard it as a 

 member of the order Heliozoa. 



(II.) Pseudospora, 1 Cienkowski, is a small Proteomyxan, 3-4 //,, which feeds 

 upon Oedogonium, Spirogyra, etc. It is related to Gymnococcus and other 

 members of Group C in producing flagellate zoospores. These zoospores, 

 provided with one or two flagella and a minute nucleus, penetrate the 

 bells of the host-plant and give rise to an Actinophrys-like stage, but 

 they do not fuse to form a plasmodium. When they are fully fed the 

 numerous pseudopodia are withdrawn and an amoeboid form is assumed 

 previous to encystment (Fig. 8, B, C). Diplophysalis, Zopf, seems to be 

 closely related to Pseudospora. 



(I.), (IV) Myxastrum, Haeckel, was found on the shores of the 

 Canary Islands and is marine. It has a stage with numerous radiating 

 pseudopodia, but forms plasmodia which attain to 0'5 mm. in diameter. 

 The plasmodium encysts as a whole and the protoplasm forms 100 or 

 more spores which give rise to amoeboid zoospores. 



(IV.) GiliophrySj Cienkowski (Fig. 8, G, H), probably belongs to this 

 group. It is similar to Nuclearia in some respects, but at times it with- 

 draws its radiating pseudopodia, becomes oval in shape, and swims rapidly 

 by means of a long flagellum. Freshwater. 



GROUP C. 

 In this group there is a stage when fine branching and anasto- 



_ J For Pseiidospora volcods, see Mastigophora, p. 168. 



