xiii, b, 5 Haughwout: Flagellated and Ciliated Protozoa 221 



ture, the parabasal body. A clear, refractile, rodlike structure, 

 originating at about the middle third of the body, runs pos- 

 teriorly and frequently projects beyond the posterior extremity 

 of the body. This is the axostyle. By some authors this is 

 believed to be a stiffening rod for maintaining the contour of 

 the body. Others speak of it as an attaching organ, while Kof oid 

 and Swezy(26) state that it is in the nature of a motile organ, 

 or, as they say, "a stout, largely intracytoplasmic fiagellum for 

 locomotion in a viscid medium." It has occurred to me that 

 it may, under some circumstances, serve as a piercing organ 

 in connection with tissue penetration. The cytostome is a 

 triangular depression at the anterior end, laterad of the median 

 line. Some writers describe a fiagellum within it, an observa- 

 tion I am unable to confirm. The endoplasm contains one or 

 more vacuoles, apparently food vacuoles, for bacteria may be 

 frequently seen within them. I have never observed a con- 

 tractile vacuole. Excretion may take place by diffusion through 

 the body wall or through the cytostome. 



Trichomonas is frequently found to bear four or even five 

 anterior flagella, which has caused certain writers to place them 

 in different genera under the euphonious, but somewhat ano- 

 malous names Tetratrichomonas and Pentatrichomonas. I shall 

 not take the time here to discuss the advisability or inadvis- 

 ability of founding new genera on such trivial variations as 

 these. 



Ohira and Noguchi(40) have created five subgenera to be in- 

 cluded under the genus Trichomonas Donne, 1837. They are: 



1. Protrichomonas Alexeieff, with three anterior flagella, 

 without an undulating membrane. 



2. Trichomastix Butschli, with three anterior flagella and 

 a trailing fiagellum (Schleppgeissel) , without an undulating 

 membrane. 



3. Trichomonas Donne, with three anterior flagella and an 

 undulating membrane. 



4. Macrostoma Alexeieff, emend. Wenyon, with three anterior 

 flagella, and an undulating membrane wedged in a deep groove 

 (peristome). 



5. Tetratrichomonas Parisi, with four anterior flagella and an 

 undulating membrane. 



To these might be added Chatter jee's Pentatrichomonas, with 

 five anterior flagella and an undulating membrane. Other intes- 

 tinal flagellates of interest here are: 



Lamblia (Giardia) intestinalis Lambl, 1859. This is an or- 

 ganism of peculiarly striking and characteristic appearance and 



