HETEROTRICHA 



547 



They noted that the parasites were only found in the mucus, never 

 in the faecal masses. They were present in very large numbers, 

 and were found to be all gametes, some of which were conjugating. 

 It appears probable that Guiart's parasites may really have been 

 C. uncinatus, and not C. dentatus. 



SUBORDER HYMENOSTOMATA Hickson, 1903. 

 Family Chiliferid.e Biitschli. — -The genus Colpoda Miiller, 1773, 

 includes the kidney -shaped Chilifera, with rows of cilia twisted from 

 left to right, commonly found in hay infusions, of which one species, 

 ~ Colpoda cucullus Schutz, 1899, commonly found in the water of 

 marshes, was noticed in a brickmaker attacked with dysentery in 

 Berlin. Uronema caudatum Dujardin, 1841, has been found in the 

 motions of cases of diarrhoea in man. 



ORDER 11. HETEROTRICHA Stein, 1859. 



The Heterotricha are free-moving Ciliata, with strong cirri or 

 membranellse, forming an adoral ring enclosing a space, the peri- 

 stome, at one part of which the mouth opens. The order is divided 

 into Polytricha, Oligotricha. 



Polytricha Hickson, 1903. — ^Heterotricha in which the surface of 

 the body is covered with rows of short cilia. 



Families. — Plagiostominidce Claparede and Lachmann, Bursa- 

 rimdcB Biitschli, StentorinidcB Stein, Gyrocoryno! Stein. 



Family Bursariid^e Kent, 1880. 



Synonym. — Bursarinidce Biitschli. 



This family includes the genus Balantidium. 



Genus Balantidium Claparede and Lachmann, 1858. 



Definition. — Bursarinidce with a large peristome and a well- 

 marked anal aperture. 



Remarks. — -Balantidium is common in the rectum of pigs, and 

 is sometimes found in the intestines of man. Cyst 80-100 in 

 diameter. 



Balantidium coli Malmsten, 1857. 



Synonyms. — Paramcecium coli Malmsten, 1857; Plagiostoma coli 

 Claparede and Lachmann, 1858; Leucophrys coli Stein, i860; Balan- 

 tidium coli Stein, 1867; Holophrya coli Leuckart, 1863. 



Balantidium coli is constantly found in pigs, and has been found 

 in the colon and the dejecta of man in cases of cholera and diarrhoea. 



In shape it is oval, slightly pointed anteriorly, but this depends 

 upon whether the peristome is funnel-shaped or contracted. It is 

 covered with cilia arranged in parallel rows, which give it a striated 

 appearance. 



it is 0 -06 to 0 -I millimetre in length by 0 -05 to 0 -07 millimetre in 

 breadth, and possesses a bean- or kidney-shaped macronucleus, and 



