
956 THE AMERICAN NATURALIST. [Vor. XXXVI. 
a, Body elongate ; 4.5 mm. long: in intestine of Cottus scorpius 
S. sobrinus Lev. (33) 
a, Number of oral spines about 48, 24 being in each row ; body broad, 
lanceolate; testes and ovary in contact with each other; 1.14- 
1.85 mm. long, 0.37-0.64 mm. wide: in intestine of flounder (Para- 
lichthys dentatus) Rance ha a S. dentatus Linton (39, 4°) 
GENUS RHOPALIAS. 
Body elongate, tapering towards the hinder end; tentacles long, being 
up to 1.3 mm. in length; prepharynx and cesophagus of about same length ; 
6-9 mm. long, o.8-1.16 mm. wide: in intestine and stomach of opossum 
(Didelphys virginiana). . + + + + + ss R. coronatus R. (80, 7) 
SUBFAMILY PSILOSTOMIN. 
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. Body subcylindrical, anterior end cylindrical and very contractile, 
without spines; acetabulum larger than oral sucker; prepharynx, 
„pharynx, and cesophagus present; yolk glands very voluminous and 
extend from acetabulum to posterior end, filling the body behind 
the testes, but not in front of acetabulum; 0.88-1.42 mm. long, 
0.25 mm. wide: in intestine of hake (Merluccius biliniaris) et al. 
Distomum vitellosum Linton (39, 4°) 
a, Body elliptical, depressed, anterior end cylindrical, contractile, without 
spines; yolk glands extend from pharynx in front of acetabulum 
to hinder end, usually not overlapping the intestinal coeca; pre- 
pharynx, pharynx, and «esophagus present; 1.6-2.74 mm. long, 
0.57 mm. wide: in intestine of flounder (Paralichthys dentatus) 
Distomum pudens Linton (39. 4°) 
. Body elongate, linear, spinose; yolk glands extend from acetabulum 
to hinder end of body; prepharynx, pharynx, and short cesophagus 
present; 3 mm. long, 0.55 mm. wide: in intestine of cod 
Distomum rachion (Cob.) Linton (38) 
a, Body elliptical or piriform, covered with flat scalelike spines; acetab- 
ulum of same size as oral sucker in middle of body; ovary to right 
of and near acetabulum; yolk glands voluminous, extending from 
pharynx -in front of acetabulum to hinder end of body, filling it 
back of testes; prepharynx, pharynx, and cesophagus present; 
0.26-0.36 mm. long, 0.12-0.18 mm. wide: in pyloric coeca of rud- 
der fish (Palinurichthys perciformis) et al. 
Distomum pyriforme Linton (39, 4°) 
a, Body elliptical; acetabulum larger than oral sucker ; anterior dorsal 
surface papillose; prepharynx, pharynx, and «esophagus present ; 
yolk glands voluminous, occupying hinder half of body; 3.10 mm. 
long, 0.86 mm. wide: in intestine of filefish (A/utera schoepfit) 
ELE. Distomum pallens (R.) Linton (38, 40) 
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