AMOEBAEA 223 



contractile vacuoles. This genus may be looked upon as a 

 primitive parasitic amoeba. 



Hyd'ramoeba hydroxena (Entz) (Fig. 88, c, d).' Parasitic in 

 various species of Hydra. First found by Entz; Wermel found 

 in Russia that 90 per cent of Hydra he studied were infected; 

 Reynold and Looper made experimental studies and concluded 

 that infected Hydra die on an average in 6.8 days and that the 

 amoeba disappears in from 4 to 10 days if removed from a host 

 Hydra. The body is more or less rounded with blunt lobopodia. 

 Size 60 to 380 microns. The nucleus shows some twenty re- 

 fractile peripheral granules in life. Contractile vacuoles are 

 one to many. Food vacuoles contain the contents of the host 

 cell such as pigments, nuclei, cnidoplasts, etc. It multiplies 

 by binary fission. Encystment has not yet been observed. 



Family 4 Paramoebidae Poche 



The amoebae possess a nucleus and nucleus-like secondary 

 cytoplasmic structure. These two cell-organs multiply by 

 division simultaneously. Free-living or parasitic. 



Genus Paramoeba Schaudinn. With the family characters. 



Pardmoeba pigmentifera (Grassi) (Fig. 88, e). Sluggish 

 amoeba with an average length of 30 microns. The cytoplasm 

 is distinctly differentiated. The secondary nucleus-like body is 

 larger than the nucleus. Flagellate swarmers are said to occur. 

 Parasitic in the coelom of Chaetognatha, such as Sagitta 

 claparedei, Spadella bipunctafa, S. inflata, and S. serratodentata. 



References 



A. Free-living forms 



Cash, J. 1905 The British freshwater Rhizopoda and Helio- 

 zoa. Vol. 1. 



Dellinger, O. p. 1906 Locomotion of amoebae and allied 

 forms. Jour. Exper. Zool., Vol. 3. 



Leidy, J. 1879 Freshwater Rhizopods of North America. 

 Report U. S. Geol. Surv. Terr., Vol. 12. 



Penard, E. 1902 Faune rhizopodique du Bassin du Leman. 

 Geneva. 



Schaffer, a. a. 1917 Notes on the specific and other char- 

 acteristics of Amoeba pr oteus' VsWdiS (Leidy), A. discoides 



