PAROPISTHORCHIS 



2 55 



roach (Leuciscus rutihis). Both species of fish as well as others are 

 readily eaten raw by man on the Courland lagoon (Baltic). It is, more- 

 over, significant that those persons whom Askanazy found infected 

 with the cat fluke were also infected with Dibothriocephalus latus, the 

 intermediate host of which is also fish (Lota sp., Esox sp., Perca sp.). 



In one of his nine cases Winogradoff also saw a small fluke 

 covered all over with spines, which he conjectured to be the young 

 stage of Opisthorchis felineus ; as, however, according to my experi- 

 ence, this species, even in smaller specimens, is always without spines, 

 the above hypothesis cannot be accepted. It is much more probable 

 that one of the other species that also invade the liver of cats may 

 accidentally be introduced into man; we know, in fact, that Metorchis 

 albidus, Braun, and Metorchis tntncatus, Rud., are both covered with 

 spines. As, however, the spines of the first-named species are rather 

 apt to fall off, and also as it possesses a different shape (spatula-shaped), 

 it may be assumed that probably Winogradoff had found Metorchis 

 truncahis, Rud., 1819, in his patient. 



Genus. Paropisthorchis, Stephens, 1912. 



Structure as in Opisthorchis, except that the ventral sucker and genital pore occur 

 on the apex of a process or pedicle projecting from the anterior portion of the body. 

 This process is about ^ mm. long, and is retractile. 



Paropisthorchis caninus, Barker, 1912. 



Syn. : Distoma co?ijunctum, Lewis and Cunningham, 1872 ; Opisthorchis noverca, 

 M. Braun, 1903 (pro parte) ; Opislhorchis caninus, Barker, 1912 (?). 



Length varies from 2*75 to 5*75 mm. in preserved specimens, average 

 3*6 to 5' 2 mm. Body uniformly spinose, though as a rule spines are 

 not present on the pedicle. Body slightly concavo-convex, the con- 

 cavity being ventral. Oral sucker 0*28 mm. Pharynx 0*224 by 

 0*184 mm. CEsophagus o'Od mm. Ventral sucker 0*176 mm. in 

 diameter. Pedicle about \ mm? long, may be completely retracted. 



Genital Pore opens on the apex of the pedicle in front of the 

 ventral sucker. Its exact position varies with the state of contraction 

 of the parts. In certain cases it actually opens within the cuticular 

 border of the sucker, in other cases it opens externally to the sucker 

 and anterior to it. The opening is covered with scales. The vas 

 deferens and uterus run alongside one another until they merge near 

 the apex of the pedicle into a common sinus. 



Vitellaria consist of eight acini on each side, extending from 

 slightly behind the base of the pedicle to the anterior border of the 

 ovary, or as far back as a line separating the posterior border of the 

 ovarv from the anterior border of the anterior testis. 



