340 MASTIGOPHORA AND PROTOMONADINA 



Prowazekia urinaria Hassall, 1859. 



This species has several times been found in human urine which 

 has been passed some hours. 



Morphology. — The flagellate appears in three forms- — a sausage- 

 shaped form, 10 to 25 ju in length by 2-5 to 6 in breadth ; a round 

 or oval form, varying from 4 in diameter to 15 by 10/^ in measure- 

 ment; a carrot-shaped form, varying from 6 by 3 to 25 by 4 

 The cytoplasm contains a large number of small, highly refractile 

 granules, and contains a trophonucleus and a kinetonucleus, which 

 latter is a relatively large pear-shaped body. The body is enclosed 

 by a thin periplast, and possesses two flagella, a shorter anterior 

 and a longer lateral, which arise fromblepharoplasts (basal granules), 

 which are connected by rhizoplasts to the kinetonucleus. There 

 is a cytostome situate near the root of the short flagellum. 



Bionomics. — It moves in a jerky manner, with the short flagellum 

 directed forwards and the long flagellum backwards. The small 

 flagellum is also useful in capturing food, such as bacteria. Food 

 enters by means of the cytostome and forms the usual food vacuoles, 

 which accumulate at the aflagellar end. A contractile vacuole is 

 seen in large flagellates, and may measure i to 3 in diameter. 

 It is situate near the base of the cytostome, to which it is joined by a 

 minute canal. It contracts every 15 to 30 seconds at a temperature 

 of 20° C. It is thought to be the dilated fundus of the cyto- 

 stome. 



Life-History.— It divides in two by binary fission, the blepharo- 

 plast apparently dividing first and forming two new flagella, after 

 which the cell nuclei and the cell divide. It can lose its flagella, 

 and can form round or oval cysts 5 to 7 in diameter, inside from 

 which after a time it again becomes flagellate, and escapes in its 

 typical form. 



Cultivation.— In association with bacteria it grows well in urine, 

 on salt agar, nutrient agar, serum agar, blood agar, peptone, salt 

 solution, nutrient broth, and diluted blood-serum at a temperature 

 of 20° C, but is killed by a temperature of 37° C. in one or two hours. 

 It has not been cultivated free from bacteria. 



Prowazekia asiatica Castellani and Chalmers, 1910. 



Synonym. — Bodo asiaticus Castellani and Chalmers, 1910. 



This flagellate was found in 1909 by Castellani and Chalmers in 

 the stools of cases of ankylostomiasis suffering from diarrhoea in 

 Ceylon. It was studied in detail by Whitmore in 1911, and assigned 

 to the new genus Prowazekia, which Hartmann and Chagas had 

 differentiated from the old genwsBodo. 



Morphology. —P. asiatica is found in the motions in two forms — 

 either as a long, slender flagellate measuring 10 to 16 in length by 

 5 to 8 in breadth or as a more rounded form, which has a trans- 

 verse diameter of 8 to 10//. The cytoplasm is alveolar in structure, 



