30 PEOTOZOA 



2. PHYLLOMITUS Stein. Body elongate and very flexible, with 2 

 flagella shorter than the body: 1 species. 



P. amylophagus Klebs (Fig. 30). Length .018 mm.: in fresh water. 



3. OXYRRHIS Dujardin. Body oval with pointed hinder end, at 

 side of which is a deep cavity from which the flagella emerge : 1 species ; 

 marine. 



0. marina Duj. (Fig. 31). Length .04 mm.: at Woods Hole. 



ORDER 5. TRYPANOSOMATIDA. 



Body elongate, usually pointed, with an undulating lateral mem- 

 brane and 1 or 2 flagella which arise from a special nucleus (blepharo- 

 plast) and accompany the membrane as a lateral chord: 1 family. 



FAMILY TRYPANOSOMIDAE. 



With the characters of the order: several genera; parasitic in 

 invertebrate and vertebrate hosts and often the cause of deadly diseases. 



Fig. 32 Fig. 33 Fig. 34 



Fig. 32 Trypanosoma gambiense (Doflein). Fig. 33 Trypanosoma brucei (Doflein). 

 Fig. 34 Hexamitus inflatus (Conn). 



TRYPANOSOMA Gruby. But 1 flagellum present: over 60 species, 

 which are parasites of the blood system in all kinds of vertebrates and 

 are also found in the intestine of various blood-sucking insects, which 

 in many cases are known to convey the parasite to the vertebrate host 

 by their bite. 



T. gambiense Button (Fig. 32). The cause of the deadly sleeping 

 sickness which affects man in western and central Africa ; it is conveyed 

 by Glossina palpalis, a tsetse fly ; length .03 mm. 



T. brucei Plimmer and Bradford (Fig. 33). The cause of nagana, a 

 sickness fatal to horses and cattle and other animals in Africa and is 

 conveyed by Glossina morsitans, a tsetse fly. 



T. evansi Steel. The cause of surra,* a fatal disease to horses and 

 cattle in Africa, Asia, and America and conveyed by horse flies. 



ORDER 6. POLYMASTIGIDA. 



Three or more flagella and usually several mouth openings present; 

 body colorless and without shell: 3 families. 



* See "Collected Studies on the Insect Transmission of Trypanosoma evansi," by 

 M. B. Mitzraain, Bull. 94, Hyg. Lab., Wash., 1914, 



