RHIZOPODA . 29 



ties of the body. Fecundation anisogamous ; spores have shells 

 without polar bodies, mostly with several sporozoites. 



Order 3. Hcemosporidia. Parasites of the blood corpuscles of verte- 

 brate animals ; they exhibit amoeboid movements ; present alterna- 

 tion of generations and hosts ; spores naked. 



Sub-class 2. Neosporidia. They are polynucleated in the adult state ; 

 the form of the body varies exceedingly ; sporulation commences 

 even before the completion of growth. . 



Order i. Myxosporidia. The spores have shells, with or without caudal 

 appendages, with two, rarety four, polar capsules. They live free 

 in such organs as the gall or urinary bladder, but are chiefly 

 found in connective tissue, and especially in fishes. 



Order 2. Microsporidia. Spores with shells ; no caudal appendage, 

 with one polar capsule. They usually live in the tissues of the 

 arthropoda. 



Order 3. Sarcosporidia. Elongated parasites of the muscular fibres of 

 amniotic vertebrate animals, on rare occasions they occur also 

 in the connective tissue ; the spores are naked, have no polar 

 bodies (?) ; kidney- or sickle- shaped. 



Class IV. Infusoria (Ciliata). The body is generally uniform in shape, 

 with cilia, contractile vacuole, frequently also with cytostom ; usually has 

 macro- and micro- nucleus ; live free in water and also parasitically. 



The orders Holotricha, Heterotricha, Hypotricha and Peritricha are classified 

 according to the arrangement of the cilia. 



Class V. Suctoria are bodies with suctorial tubes, contractile vacuoles, 

 macro- and micro- nucleus, no cytostom. They generally invade aquatic 

 animals as space parasites, yet also attack plants ; early stage ciliated. Live 

 frequently as parasites in infusoria. 



LITERATURE. 



Besides the zoological works (compare Btitschli and A. Lang) and those already 



alluded to, the following may be noted : 



PFEIFFER, L. Die Protoz. als Krankheitserreger. 2nd edit. Jena, 1891. Supple- 

 ments, Jena, 1895. 



SCHNEIDEMUHL, G. Die Protoz. als Krankheitserreger der Menschen u. der Haus- 

 thiere. Leipzig, 1898. 



DOFLEIN, F. Die Protoz. als Parasiten und Krankheitserreger. Jena, 1901 ; and the 

 2nd edit, of the book. 



Class I. Rhizopoda. 



Order i. Amcebina. 

 Gen. i. Amoeba, Ehrbg. 



The body of the amoeba, which is always naked, frequently exhibits the 

 differentiation of the ecto- and endo- sarc very distinctly ; the ectosarc is 

 viscid and hyaline, the endosarc is liquid and granular, and in addition 

 contains food-particles (free in the plasma or enclosed in vacuoles), fatty 

 granules; incidentally also crystals. It contains, moreover, the compact 

 or vesicular nucleus, which occurs singly in nearly all species, and the con- 

 tractile vacuole which discharges its watery contents with acid reaction to 



