30 
Genus OPISTHORCHIS Blanchard, « 189S. 
Fig. 40. —Egg of Lan- 
cet Fluke {Dicro- 
ccdium Innceatum) , 
with contained 
embryo, x 700. 
(After Leuckart, 
1889, p. 379, tig.171.) 
Gexeric diagnosis. — Fasciolidse; Body distinctly, often yery greatly, elongated; 
anterior end attenuated, posterior end broader. Skin smooth, often without spines. 
Suckers not far separated, and usually not especially large. Intestine with pharynx, 
short slender esophagus, and long simple ceca. Excretory 
system with long sigmoid stem usually winding between 
the testicles, and lyith short branches. Genital pore 
median, immediately in front of aceta- 
bulum. Copulatory organs absent. Male 
organs: Testicles in posterior portion of 
body, one posterior of the other, more 
or less distinctly lobate, or eyen branched. 
Female organs: Oyary simple or lobate, 
anterior of testicles; Laurer’s canal pres- 
ent; receptaculum seminis yery greatly 
deyeloped; uterine coils anterior of tes- 
ticles and oyary, but not extending ma- 
terially oyer the intestinal ceca; yitellaria 
moderately deyeloped, lateral of intestinal 
ceca, not extending anteriorly beyond 
the yentral acetabulum. 
H.\bitat. — Parasitic in the gall-ducts 
of warm-blooded animals (mammals and 
liirds). 
Type species. — Opisthorchis felineiis (Riyolta, 1884 
KEY TO SPECIES OF OPIS- 
TIIORCrilS REPORTED 
FOR MAN. 
(For species thus far 
found in the United 
States, follow Roman 
} Fig. 41. — Free embryo (miraciclium) of 
1. Testicles branched, Lancet Fluke; A, lateral Anew; B, 
and frequently ex- dorsal view. (After Leuckart, 1889, p. 
tending beyond the 385, fig. 175 A, B.) 
intestinal ceca into the lateral fields; excretory 
system runs dorsally of testicles; Asia, but im- 
ported cases elsewhere 0. sinensis (p. 35) 
Testicles may he lobate, hut not branched, and are con- 
fined to median field hetiueen the intestined ceca; 
excretory system sigmoid extending between the 
testicles 2 
2. Spines present on shin; vitellaria exieiid, caudally of 
first testicle to about the anterior border of posterior 
testicle; vjorm not over 12 mm. long; ventral 
acetabidum close to bifurcation of intestine; 
India 0. noverca (p. 33) 
Spines absent; vitellaria not reaching or barely reach- 
ing the first testicle; worm 10 to 18 mm. long; ventral acetabidum some distance from 
bifurcation of intestine; Europe 0. felineus (p. 31) 
Fig. 39. — Lancet Fluke, 
enlarged to show the 
anatomic characters: ac, 
acetabulum; c. p., cirrus 
pouch; i, intestinal ceca; 
VI, mouth with oral 
sucker; or., ovary; e, eso- 
phagus; p. b., xiharyngeal 
bulb; t, lobate testicle.s; 
ut., uterus; va, vagina; vg, 
vitellogene glands. (After 
Stiles & Hassall, 1894, PI. 
4, fig. 19.) 
« Synonyms. — Opisthorchis Blanchard, 1895; Opistorchis Railliet, 1896 (misprint); 
“ Campula Cobbold,” of Stiles & Hassall, 1898 (in part) ; Opisthorchic Stiles, 1901 (mis- 
print). 
