29 
posterior of them, receptaculum seminis and Laiirer’s canal present; vitellaria mod- 
erately developed, lateral of the intestinal ceca; uterine coils numerous, distinctly 
transverse, confined to space posterior of genital glands. Eggs quite numerous; 
Fig. 38 . — Limnsea viator , natural size and enlarged. 
(After d’Orbigny.) 
vlien ripe of a more or less deep brown color, and varying in size from 36 to 47 f.i 
by 21 to 31/1. 
Habitat. — IVitli one exception, parasitic in liver and gall bladder of warm-blooded 
animals (mammals and birds). 
Type-species. — Dicroccdium lanceatum Stiles & Hassall, 1896. 
The Lancet Fluke— DICROCCELIUM LANCEATUM ff Stiles & Hassall, 1896— 
of Ruminants, Man, etc. 
[Figs. 39 to 41.] 
Specific diagnosis. — Dicrocceliiim : 4 to 9 mm. long, 2 to 2.4 mm. broad; thin, 
lanceolate, more pointed anteriorally than posteriorly. Acetabulum slightly larger 
than oral sucker, the latter slightly subterminal; distance between the two, about 
one-fifth the length of the body. Skin without spines. Pharynx small (0.25 mm. ), 
globular; esophagus about 2.5 to 3 times as long as the pharynx, so that the bifurca- 
tion of the intestine is immediately anterior of the genital jiore; intestinal ceca extend 
to posterior quarter of body. Genital pore about halfway between suckers, imme- 
diately posterior of bifurcation of intestine. Mah organs: Cirrus pouch extends from 
genital pore to ventral acetabulum and contains the pars prostatica and vesicula 
seminalis; .testicles irregularly lobate, one caudad of the other, directly caudad of 
ventral acetabulum. Female organs: Ovary small, directly caudad of posterior 
testicle, but anterior of transverse vitelloducts; uterus confined between the intestinal 
ceca, but in posterior fourth of body there is a tendency for the coils to extend nearer 
the lateral margins; vitellaria only moderately developed, marginal, in equatorial 
third of body. Eggs 38 to 45 /.l long by 22 to 30 j.i broad, contain embryos when 
oviposited. Sporocyst, redia, cercaria, and intermediate host undetermined. 
Habitat. — Gall ducts of cattle {Bos taunts), sheep {Oris aries), ass {Equus asinus), 
man {Homo sapiens), etc. 
Geographic distribution. — Very extended, especially in Europe, but apparently 
not in England or Xorth America. 
« Vernacular names. — English, Lancet fluke; German, der lanzettfdrmige Leberegel, 
das lanzettfdrmige Doppelloch; Erench, distome lanceole; Italian, distoma lanceolato. 
Synonyms. — Eascio/aVa?iccotoa Eudolphi, 1803 (not Schrank, 1790); Bistoma I ance- 
olatum (Eudolphi) Mehlis, 1825; “Distoma {Dicrocceliuin) lanceolatuni Mehlis” of 
Dujardin, 1845; “ Distomum lanceolatuni Mehlis” of Diesing, 1850; “Dicroccdium 
lanceolatuni Dujardin” of Weinland, 1858; “Fasciola Bucliliolzii Jordens, 1801,” mis- 
print of Braun, 1889; Dicrocceliuin lanceatum Stiles & Hassall, 1896. 
Bibliography. — Xo extensive bibliography as yet published. Eor detailed tech- 
nical discussion see Leuckart (1889, pp. 359'-399). For a review of seven cases of 
infection compiled for man consult Blanchard, 1888a, pp. 611-612, Leuckart, 1899, 
pp. 391-399, or Moniez, 1896, pp. 120-122. 
