52 Structure and Classification of Micro-organisms 



Family Trypanosomida. Body delicately fusiform. Con- 

 tains a nucleus, a blepharoplast or centrosome, and an 

 undulating membrane. A single wavy flagellum arises 

 in the posterior part of the body close to the centrosome, 

 passes along the edge of the undulating membrane to the 

 anterior extremity, where it continues free for some dis- 

 tance. Nutrition parasitic. Reproduces by division. 

 Genus Trypanosoma. 

 " Leishmania. 



Babesia. 



Family Spiroch<ztid(B. Organisms very long and spirally 



twisted. Nucleus indistinct. Multiplication probably 



by longitudinal division only. Nutrition is parasitic or 



saprophytic. 



Genus Spirochaeta. Body flattened, with a very narrow 



undulating membrane. 



Genus Treponema. Body not flattened. No undulating 

 membrane. Extremities sharp pointed and terminating 

 in short flagella. 



Class Sporozoa (cxopof a spore, faov an animal). Organisms 

 unprovided with cilia or flagella in the adult stage. Always 

 endoparasites in the cells, tissues, or cavities of other animals. 

 Nutrition is parasitic and osmotic. Reproduction always by 

 spore-formation, the germs or sporozoites either being produced 

 by the parent or indirectly from spores, into which the parent 

 divides. 

 Subclass Telosporidia. Spore-formation ends the individual life, 



the entire organism being transformed to spores. 

 Order GREGARINIDA. Possess distinct membrane with myo- 

 nemes during adult life; locomotion mainly by contraction. 

 Young stages alone (cephalonts) are intracellular parasites, 

 the adults (sporonts) being found in the digestive tract or the 

 body cavities. Sporulation takes place after or without 

 conjugation, but within a cyst that is never formed, while 

 the parasite is intracellular. 



Order COCCIDIIDA. Spherical or ovoid in form, without a 

 free and motile adult stage. Never ameboid. Sporula- 

 tion takes place within cysts formed while the organism is 

 an intracellular parasite. 

 Genus Coccidium. 



" Eimeria. 



Order H^MOSPORIDIIDA. Sporozoa of small size living in the 

 blood-corpuscles or plasma of vertebrates. The adult 

 form is mobile and in some cases provided with myonemes. 

 Reproduction by endogenous or asexual sporulation, while 

 in the host or by exogenous sporulation after conjugation. 

 Genus Plasmodium. 



Subclass Neosporidia. Organisms that form sporocysts through- 

 out life, the entire cell not being used up in the formation of 

 the spores. 



Order SARCOSPORIDIA. The initial stage of the life history is 

 passed in the muscle cells of vertebrates. Form is 

 elongate, tubular, oval, or even spherical. Cysts have a 

 double membrane, in which reniform or falciform sporo- 

 zoites are formed. 

 Genus Sarcocystis. 

 " Miescheria. 

 " Balbiania. 



