200 The Philippine Joutmal of Science leis 



Subphylum MASTIGOPHORA— Continued. 

 Class Zoomastigopliora — Continued. 

 Subclass Lissoflagellata — Continued. 



Order Spirochsetida. — The systematic position of this group is still 

 unsettled, and they are grouped with the flagellates largely as 

 a matter of convenience. The tendency is to place them in a 

 group intermediate between the Protozoa and the Bacteria. 

 However, that question cannot be entered into here. These 

 organisms have spiral, flexible, somewhat plastic bodies, through 

 which the chromatin is distributed in the form of granules, or 

 blocks, or possibly as a helix. Some forms are described as 

 having a crista or nonkinetic membrane running along the body 

 and superficially resembling the undulating membrane of the 

 trypanosomes, to which, however, it is not analogous. Trans- 

 verse and longitudinal division is described. Other writers 

 describe a multiple transverse division (granule formation) or 

 the formation of coccoid bodies. Life histories are very incom- 

 plete. The order includes many parasitic species, some of which 

 are highly pathogenic. Others are free-living. Typical genera: 

 Spirochseta, Cristispira, Saprospira, Treponema, and Leptospira. 

 Order Monadida. — Mastigophora of the simpler type. The bodies are 

 plastic and sometimes amoeboid. One or more flagella occur at 

 the anterior end. Many saprozoic forms. The holozoic forms 

 have no definite mouth opening, the food being driven down to 

 the base of the flagellimi and ingested by a specialized area of 

 soft protoplasm at that point. 

 Family Rhizomastigidae. — The body is amoeboid. The pseudopodia 

 may be lobose like the Rhizopoda or axial as in the Actinopoda. 

 There are one or two flagella. The flagella and pseudopodia 

 cooperate in food-taking. Typical genus, Mastigamoeba 

 Schultze, 1875. 

 Family Cercomonadidae. — There is no actual pseudopodia fonna- 

 tion, but the cells are frequently very plastic and changeable 

 in form. There is one flagellum with a flagellum-fissure at 

 its base. Nutrition is holozoic or saprozoic. The family 

 includes many parasites. Typical genera: Cercomonas Du- 

 jardin, 1841; Herpetomonas Kent, 1880; Leishmania Rogers, 

 1905. 

 Family Codonecidae. — Minute, colorless "monad" forms. They 

 secrete and remain in membranous or gelatinous cups. Tjrp- 

 ical genus, Codoneca James-Clark, 1866. 

 Family Bikecidae. — The base is broader than the anterior 

 extremity and bears a tentaclelike process. The individuals 

 are minute and may form colonies. Nutrition is holozoic. 

 Typical genus, Poteriodendron Stein, 1878. 

 Family Heteromonadidae. — Minute, colorless "monads" that, in 

 addition to the principal flagellum, possess one or more 

 accessory flagella. They frequently give rise to beautiful 

 colonies, which form on a common stalk. Typical genus, 

 Anthophysa St. Vincent, 1824. 

 Order Heteromastigida. — The distinguishing characteristic of the 

 order is the possession of two or more flagella, one of which is 



