264 



THE ANIMAL PARASITES OF MAN 



This species was discovered in 1851 by Bilharz in the intestine 

 of a boy who died in Cairo ; a second case was only found in 1891 

 and published by R. Blanchard, so that it appeared as if the species 

 were very scarce. According to Looss, this is, however, not the case, 

 but the species easily escapes notice on account of its small size. 

 Looss found it in Alexandria twice in nine autopsies, and once in 

 Cairo, and has recently stated that in man " it is not at all uncommon 

 to meet with the parasite in cadavers, and the eggs of the worm in 

 the stools of the patients." Leiper records one case from Japan 

 and one from China. The parasites occupy the middle third of the 

 small intestine, and even when present in large numbers appear to be 



harmless. 



This small species, according to 

 Looss, frequently occurs in Egyptian 

 clogs, less so in cats, and has also been 

 found in the fox, as well as once in 

 Milvus pamsiticns ; Janson also reports 

 this species from the intestine of the 

 dog in Japan. 



Metagonimus, Katsurada, 1913 ; 

 Yokogawa, Leiper, 1913. 



Resembles in general structure 

 Heterophyes. In the arrangement of 

 its ventral genital suckers resembles 

 but differs from that of Tocotrema, 1 

 Looss. The ventral and genital suckers 

 lie laterally and on the right. 



Metagonimus yokogawai. Katsurada, 



Syn. : Yokogawa yokogawai, Leiper, 1913. 



FIG. i64.-Mtiagonimus yokogawai, One to i '5 mm. long, seldom 2-5 mm., 

 Katsurada, 1913: the spines are only and O'A to 07 mm. broad ' elliptical in 



shown over a small pait of the skin. , rr*t M i ,1 i i 



(After Leiper.) shape. 1 he body is thickly covered 



with nail-shaped spines about 10 //, 



long. Oral sucker 77 p to 85 //, in diameter. Ventral sucker charac- 

 teristic and peculiar O'i2 to 0-14 mm. by 0-08 to i mm. It is a sac-like 

 organ placed deeply in the body, but does not open as in other flukes on 

 the ventral surface. Testes elliptical, not quite symmetrically placed at 

 the hind end of the body. Vesicula seminalis retort-shaped, situated 

 transversely, internal to the ventral sucker. Pars prostatica present. 



1 In the genus Tocotrema the common genital duct opens into the ventral sucker. 



