
No. 432.] WORTH-AMERICAN INVERTEBRATES. 965 
GENUS DIPLOSTOMUM. 
4,. Acetabulum and oral sucker small ; special organ of attachment of a 
large cavity at bottom of a conical projection just back of acetabu- 
lum, in the center of which is a short canal leading to the cavity, 
3-4 mm. long: in intestine of Strix nivea et al. 
D. grande Dies. (23, 80) 
. Special organ of attachment open; acetabulum and oral sucker small ; 
a, 
1 mm. long, 0.35 mm. wide; a larval form found in cysts in liver of 
Pomotis vulgaris etal. . D. cuticola Dies, (21, 38, 80) 
@,. Acetabulum large; oral sicker very small ; anterior portion of body 
longer than hinder portion and not sharply separated from it; special 
organ of attachment an elliptical depression; 3.5-4.5 mm. long: in 
intestine of alligator D. pseudostomum Will.-S. (96) 
GENUS POLYCOTYLE. 
Oral and ventral suckers small; 14 mid-dorsal suckers ; 4.5 mm. long: 
in intestine of alligator. . . P. ornata Will.-S. (Fig. 110) (96) 
GENUS HOLOSTOMUM. 
Body spinose, “divided by a constriction at the anterior third." 
* Head ovoidal, mouth terminal, round, opening into a cup-shaped 
pharynx"'; 3.2 mm. long, 0.8 mm. wide: in intestine of Rana pipiens 
H. nitidum Leidy (21) 
Body not spinose ; ventral sucker twice as large as oral sucker; ventral 
projection slit longitudinally into several parts and not extending 
beyond cup; 4-5 mm. long: in intestine of Ardea her 
H. cornu Nitzsch (21, 80) 
Anterior part of body subglobose, variable, aperture transverse; pos- 
terior cylindrical; reproductive aperture terminal surrounded by a 
muscular border and with a central conical protractile part; 3 mm. 
long, o. 8 mm. wide: in intestine of Circus cyaneus 
H. variabile Nitzsch (Fig. 113) (36) 
GENUS GASTEROSTOMUM. 
Body elliptical; mouth in center of body; 4-6 mm. long: in pyloric 
appendages of Cottus scorpius . G. armatum Mol. (Fig. 114) (33) 
a, Body ovate, being wider anteriorly ; mouth towards anterior end ; : » 
2.7 mm. long, 0.92-1 mm. wide: in intestine of Zobofes su 
Monostomum orbiculare (R.) aes ati 
— G. ovatum Linton (39) 
1.28-2.7 mm. long, 
e. 
. Body elongate; mouth towards anterior end; 
0.21 mm. wide: in intestine of Sarda sarda 
G. arcuatum Linton (39, 40) 
