386 BIOLOGY OF THE PROTOZOA 



Hematococcus as well as parasitic flagellates, particularly Tricho- 

 monas, and nuclei of amebae; ciliates of various kinds, and other 

 rhizopods are destroyed by Nucleophaga. Algae, diatoms, plant 

 and animal flagellates are all subject to infection by species of 

 Pseudospora. 



The thick cellulose walls of various plant types may be dissolved 

 by amylolytic ferments formed by certain types. In such cases no 

 sharp line can be drawn between parasitism in a strict sense and 

 processes of holozoic nutrition. These are well illustrated by 

 Vampyrella spirogyrae which feeds on Spirogyra cells; V. lateritia, 

 Leidy, on algae of different kinds, and V. vorax, Klein, which lives 

 on diatoms. 



# Serious and economically troublesome diseases of plants are 

 caused by parasites belonging to the Mycetozoa. 



Plasmodiophora brassicae, Woronin, is the best known of this 

 group largely because of its economic importance. It attacks the 

 roots of cabbages and other Cruciferae and produces a character- 

 istic tumor disease known as "Club-root," "Hanberries," "Fingers 

 and Toes," " Kohlhernie," etc. 



Minute flagellulae are formed from the cysts in an infected garden 

 and these, in some way, penetrate the root cells of the plant and 

 become myxamebae. The nuclei multiply and they grow in the 

 cells of the plant, different individuals fusing to form plasmodial 

 masses which fill the cell. With exhaustion of the cell contents the 

 process of reproduction begins and results in the formation of 

 great masses of uninucleate " spores." 



Invertebrates have not been thoroughly investigated for ameboid 

 parasites, and a big field is open here for research. The earliest on 

 record is a parasite of cockroaches to which Leidy, in 1879, gave 

 the name Endamoeba blattae. Endamoeba minchini was described 

 by MacKinnon (1914) from the intestine of the crane-fly Tipula sp.; 

 Amoeba chironomi, Porter (1909), from larvae of Chironomus; 

 Endamoeba belostomi (Brug, 1922) from the water-bug Belostoma sp. 

 of Java and E. disparata, E. simulans and E. asbulosa, Kirby 

 (1927), from termites. A species from the gut of the oyster (Val- 

 kampfia paiuxent, Hogue) was described by Hogue (1921). End- 

 amebae from other insects include: E. apis, Fantham and Porter 

 (1911), in the honey bee; E. mesnili, Keilin (1917), in larvae of 

 Trichocera sp.; E. thompsoni in Blatta orientalis. 



In entomostraca (Daphnia species) a curious sporulating ameboid 

 parasite was discovered by Chatton (1925) and named by him 

 Pansporella perplexa. Binucleated spores escape from thin-walled 

 cysts in the gut of Daplmia and give rise to uninucleate amebae, 

 whether by division or by fusion of nuclei was not determined. 

 These grow without dividing and finally encyst in which form they 

 are passed out of the intestine. A series of nuclear divisions occur 



