OPISTHORCHIID^ 



575 



Life-History, — ^According to Nakagawa, the miracidia infect the 

 snails Melania lihertina and Melania obiiquegranosa. 



Nagakawa in Formosa found encysted larvae in fresh-water 

 crabs: — -i. Geothelphusa obtusipes. Synonyms. — Potamon obtusipes, 

 Thelphusa rubra. 2. Geothelphusa dehaanii. Synonyms. — Potamon 

 dehaanii, Thelphusa berardi, and perhaps — -3. Eriocheir japonicus. 

 Synonym.— E.formosa. 



According to Sadao Yoshida, in the first two, the larvae are found 

 in the liver, rarely in the gills or muscles, and in the last chiefly in the 

 gills, muscles, and hypoderm, and rarely in the liver. 



Dogs and cats have been infected by these observers from the 

 crabs, when the larva, escaping from the cyst in the intestine, pene- 

 trates the wall near the jejunum and enters the abdominal cavity, 

 perforates the diaphragm, and, entering the subpleural tissue, 

 may pierce its way into the lung and encyst or pass into the neck 

 (and perhaps so to the brain, etc.). The lungs are their favourite 

 seat, and the only one in which they attain maturity. 



Kakami, on the other hand, says that cercariae may be found in 

 Melania libertina, and that they get into drinking-water and so 

 infect people directly. 



Pathogenicity.— It causes paragonimiasis in man. 



FAMILY OPISTHORCHIID.E Braun, 1901, emendavit 

 Stephens, 1916. 



Definition. — ^Fascioloidea, hermaphroditic, with oral sucker with- 

 out collar of spines. Ovary in front of testes. Genital pore behind 

 ventral sucker. Cuticle without pointed spines. Small to medium 

 flukes tapering anteriorly. Cirrus absent, but receptaculum seminis 

 and Laurer's canal present. Eggs small. 



Classification. — -Tlxe family is divided into subfamilies as follows : — 



A. Excretory pore terminal ; bladder long, dorsal to 



testes. 



Uterine coils not [overlapping intestinal caeca — Opisthor- 

 chiincB. 



B. Excretory pore ventral; bladder short, ventral to testes. 

 Uterine coils overlapping intestinal caeca — Metorchiince. 



Subfamily Opisthorchiin^ Looss, 1899, emendavit 

 Stephens, 1916. 



Definition. — ^As above. 



Classification. — -The genera important to us can be distinguished 

 as follows : — 



A. Testes lobed : — 



I. With long retractile process projecting from ventral 

 surface and^carrying out its apex the acetabulum and 

 the genital pore — Paropisthorchis. 



