Metorchis truncatus, Rud., 1819.
Fig. 162.—Metorchis truncatus, Rud.: from the biliary ducts of the domestic cat. V.s., ventral sucker; I., gut; V.sc., vitellaria; T., testes; O., ovary; R.s., receptaculum seminis; Ut., uterus. 25/1.
This species, which attains a length of 2 mm., is slender and conical, the anterior end is pointed and the posterior truncated, and provided with a muscular tuberosity that resembles a terminal sucker; for this reason the discoverer of the species (Rudolphi) classed it with the Amphistomes. The cuticle in the young, as well as in the adult specimens, is entirely and closely covered with spines. Suckers about equal in size (0·134 to 0·172 mm.); the ventral sticker lies somewhat in front of the middle of the body. The pharynx is small (0·09 mm.), the œsophagus minute, the intestinal cæca reach to the posterior extremity. Between them, and in front of their blind ends, lie the two elliptical testes, one generally a little in front of the other. In front of them, either in the median line or somewhat laterally, the spheroidal ovary is situated; in front, again, is the uterus, the coils of which usually extend beyond the median field. The vitellaria are at the sides of the central third of the body, thus commencing in front of the ventral sucker; cirrus pouch absent; the genital pore is close in front of the acetabulum. The excretory pore is terminal (?). Eggs 29 µ by 11 µ.
Metorchis truncatus lives in the bile-ducts of the seal, cat, dog, fox, and glutton (Gulo borealis). The source of infection is unknown, although one would suspect fish. Askanazy did not succeed in getting this fluke in his feeding experiments, but another species, Metorchis albidus, not uncommon in cats by feeding them on roach (Leuciscus rutilus).
Family. Heterophyiidæ, Odhner, 1914.
Genus. Heterophyes, Cobbold, 1866.
Syn.: Cotylogonimus, Lühe, 1899; Cænogonimus, Looss, 1899.
No crown of spines on head. Body divided into a narrow, movable, anterior part (neck), and a broader, less movable, posterior portion, which contains the genitalia. The suckers separated from one another by a space equal to half the length of the body or more; the pharynx is close behind the oral sucker; the œsophagus is long; the intestinal cæca extend to the posterior border; the genital pore is placed laterally, and behind the ventral sucker. Genital sucker provided with a circlet of chitinous rodlets, shaped like stags’ horns. The testes are at the posterior end, the ovary in a median position in front of them. Laurer’s canal with receptaculum seminis present; the small vitellaria are at the sides of the posterior part of the body. Parasitic in the intestine of mammals and birds.