46 PROTOZOA. 



Sub-fain. 3. Colepina. Mouth terminal, surrounded by a circle of cirri. 

 Body sometimes surrounded by armour composed of pieces of the pellicle 

 arranged in an annular manner. Plagiopogon Stein, f.w. ; Coleps Nitzsch. 

 f.w. ; Tiarina Berg, m. ; Stephanopogon Entz, m. 



Sub-fam. 4. Cyclodinina. Cilia confined to one or several rings. Mouth 

 on a papilliform projection. Didinium Stein, f.w.; Mcsodinium Stein, a 

 large oral papilla with one or more cirri arising from its base, m. and f.w. 



Sub-fam. 5. Prorotrichina. Bluntly truncated oral end ; ciliation 

 confined to front end, or there are in addition incomplete rings of cilia. 

 Butscldia Schuberg, rumen of Ruminants. 



Fain. 2. Trachelina. Mouth is either a long slit which extends from the 

 front end along the ventral surface backwards, or its hinder part is alone 

 developed as a short slit-like or roundish opening. The oral end of the body 

 usually tapers in a proboscis-like manner. Pharynx short or absent. 



Sub-fam. 1. Amphileptinse. Mouth on the convex ventral edge of the 

 dorsalwards-bent proboscis, sometimes as long slit, sometimes as round 

 opening. Ampldleptus Ehrb., m. and f.w.; Ziono^fsWrzesniowski, mouth 

 along whole ventral edge of long proboscis, f.w. and m. ; Loxophylluin, 

 Duj., f.w. and m. ; Trachelius Schrank, mouth as round opening at base of 

 proboscis, endoplasm vacuolated, f.w.; Dilcptus Duj., f.w. and m. 



Sub-fam. 2. Loxodina. Proboscis bent ventrally, and mouth on its 

 concave edge. Ciliation confined to the right side. Loxodcs Ehrb., large 

 size, endoplasm vacuolated, on dorsal side a row of excretion vacuoles, each 

 with a dark body, f.w. 



Fam. 3. Chlamydodonta. Body never elongated ; mouth always at a distance 

 from the front end. Pharynx always with well-developed rod-apparatus, or a 

 smooth, sometimes peculiarly-formed oesophageal tube. 



Sub-fam. 1. Nassulina. Ciliation complete; Nassula Ehrb., m. and f.w. 



Sub-fam. 2. CMlodontina. Ciliation confined to, or stronger on the 



ventral surface than on the back. Orthodon Gruber, m. ; Chilodon Ehrb. 



(Fig. 32), f.w. and infus., m. ; Chlamydodon Ehrb., m. ; Ojnsthodon Stein, 



mouth far back, f.w.; Phascolodon Stein ; Scaphidiodon Stein, m. 



Sub-fam. 3. Erviliina. Ciliation confined to ventral surface, or a 

 small field of it. Caudal end with a well-developed movable style usually 

 arising a little ventrally of hind end. Acgyria Clap, and L., m. ; Onycho- 

 dactylus Eutz, m. ; Trocliilia Stein, f.w. and m. ; Dystcria Huxley, f.w. 

 and m. 



Order 2. TRICHOSTOMATA. 



Mouth as a rule always open, rarely closed when not in use ; 

 pharynx always tubular and open ; edges of mouth provided witli 

 undulating membranes which are continued into the pharynx, or the 

 latter is provided with cilia. Food rarely swallowed, usually brought 

 by a whirlpool or by special ciliary structures. 



Sub-order 1. ASPIROTBICHA. 



The mouth in the most primitive forms extends as a slit from the front end 

 along the ventral surface ; but is usually removed from the front end as a 

 reniform or crescent-shaped opening. Pharynx, when present, without rod- 

 apparatus. At the edges of the mouth or in the pharynx are one or two 

 undxilating membranes. 



