GENERA PHYLLOMITUS AND COSTIA 



305 



Genus: Phyllomitus Stein, 1878. 

 This genus includes Phyllomitus undulans, which was originally de- 

 scribed by Stein. Woodcock (1916) obtained it in culture from goat's 

 faeces. It has an ovoid body, and varies in size from 6 to 13 microns by 

 3 to 8 microns (Fig. U-t). There are two flagella, one about twice the 

 length of the body and the other less than half this. The two flagella 

 are united by a membrane. Multiplication is by binary fission. 



Fig. 145. — Costia necatrix from Skin of Fish. (After Moroff, 1903.) 



a. Side view of flagellate ( X 2,000). 

 b-c. Probable division forms with two new flagella developing ( X 2,000). 

 d. Section of skin with attached flagellates. e. Encysted form ( X 2,000). 



Genus: Costia Leclerq, 1890. 

 This genus was founded by Leclerq (1890) for a flagellate which is 

 parasitic on the skin of fish. The organism is pear-shaped, and has two 

 or four flagella arising in a groove. 



Costia necatrix (Henneguy, 1883).— This flagellate, the only member of 

 the genus, was discovered by Henneguy (1883, 1884). He placed it in the 

 genus Bodo as Bodo necator, while Leclerq (1890) created for it the new genus 

 I. 20 



