386 
Digenetic Trematodes in Japan 
The pharynx lies immediately behind the oral sucker; its dimensions are 
0*18 mm. x 0*15 mm. The oesophagus is short, the length being 0*15 mm. 
The intestinal caeca reach almost to the posterior end of the body and termi¬ 
nate just in front of the tongue-like appendage. The course of the intestinal 
caeca is slightly sinuate and at the place where the vitellaria are present both 
caeca are bent inwardly. 
The excretory pore opens at the posterior end. The median unpaired part 
of the vesicle runs anteriorly and at the level posterior to the ovary it divides 
into arms, which are bent at right angles. After passing over the intestinal 
caeca they again divide into anterior and posterior branches, which run along 
the lateral margins of the body and can be traced almost to the ends of the 
body. 
The testes lie immediately postero-lateral to the ventral sucker, their 
external borders touching or overlapping the intestine. They are round or 
slightly lobed into 3-5 lobes, their diameter is about 0-4-0-5 mm.; they lie at 
about the same level. 
The cirrus-pouch lies anterior to the ventral sucker and slightly to the 
right of the median plane. Its size is 0*7 mm. x 0*2 mm. The vesicula semi- 
nalis and the pars prostatica make one or two turns. The genital pore opens 
on the median line, slightly posterior to the bifurcation of the oesophagus. 
The ovary lies at about the middle part of the body, and slightly 
left of the median line. It is slightly elongated transversely, the transverse 
diameter being 0*18 mm. The vitellaria lie exterior to the intestinal caeca, at 
the level of the ovary and extending posteriorly for a short distance, and 
often extend over the intestine. They are composed of three or four ascini. 
The uterus lies in the space between the two intestinal caeca, often reaching 
outside the latter. It first runs posteriorly and then anteriorly, passing through 
the space between the left testis and the ventral sucker and runs anteriorly 
along the left side of the ventral sucker. At the anterior border of the ventral 
sucker it turns mesially and after forming a short vagina, opens exteriorly near 
the male genital pore. Along the whole course the uterus forms numerous late¬ 
ral loops. The eggs are fairly numerous, their size is0*025-0*03 mm. x 0*018 mm. 
The shell is relatively thick and the lid is flat. 
Tounger specimens measure T5 mm. x 0*45 mm.; they have an ellipsoidal 
shape, the body tapering at both ends. Both the suckers measure 0*2 mm. 
in diameter. The ventral sucker lies at the middle of the body. The alimentary 
canal, the excretory vesicle and the immature genital organs can be recognized. 
(5) Dicrocoelium macaci n. sp. (PI. XXIV, figs. 5-8). 
Diagnosis. Body-shape variable, the broadest part being near either 
anterior or posterior part; size 4*5-5 mm. x 1-1*5 mm. Cuticle with minute 
protuberances, densely crowded on the anterior body surface. Ventral sucker 
slightly larger than the oral. Intestinal caeca terminating at the posterior 
third of the body, usually unequal in length. Testes lie slightly posterior to 
