126 THE ANIMAL PARASITES OF MAN 



encysted specimens, it may be assumed that the small intestine 

 or the duodenum is their habitat. 1 



Genus 2. Nyctotherus, Leidy, 1849. 



Flat, heterotrichous infusoria, kidney- or bean- shaped. The peristome 

 commences at the anterior pole of the body and extends along the concave 

 side up to the middle, where the oral aperture is situated. The cyto- 

 pharynx runs in an oblique direction and is more or less bent. The 

 anus is at the posterior extremity, where a single contractile vacuole is also 

 situated. The macronucleus is almost in the centre of the parasite. This 

 species lives parasitically in the intestine of amphibians, insects and 

 myriapods, and one species is also found in man. 



Nyctotherus faba, Schaudinn, 1899. 



The body is bean-shaped, and a little flattened dorso-ventrally, 

 o*O26-o'O28 mm. in length, croiG-o'oiS mm. in breadth, O'oio- 



O'0i2 mm. in thickness. The 

 i 



peristome is on the right bor- 

 der and extends to the middle ; 

 at the left there are large adoral 

 cilia ; the cilia on the right 

 border not being larger than 

 those on the body ; the cyto- 

 pharynx is short, slightly bent 

 and turned backwards. The 

 contractile vacuole is large, 

 globular, situated at the pos- 

 terior extremity, and its con- 

 tents are voided through the 

 anus at its left. The macro- 

 nucleus is in the centre of the 



FIG. 65. Nyctotherus faba, Schaud. From , . , . TIT /- 



life (after Schaudinn). body ; it IS globular (O'OO6- 



0*007 mm. in size), and has 



four or five largish collections of chromatin ; the micronucleus 

 lies close to it, and is globular or somewhat elongated (o'OOi-O'ooi5 

 mm.). Cysts oval. 



This species has hitherto only been seen once in the same 

 patient in whom Balantidium minutum was discovered. 2 



1 Jakoby, M., and F. Schaudinn, " Ueb. 2 neu Inf. i. Darm d. Mensch." (C. /. B., 

 P. u. I., 1899, xxv., p. 487) ; Schulz, " Colpoda cucullus im Darm d. Mensch." (Berl. 

 klin. Wchschr., 1899, No. 16, p. 353). 



- For literature see above, Balantidium minutum. 



