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POMPHORHYNCHUS BULBOCOLLI Linkins, n. sp. 
(Pl. XXIII, Fig. 7, 8) 
Body elongate, tapering toward the posterior end. Neck prominent, 
measuring 2.6 to 4 mm. in length; diameter 0.15 to 0.4 mm. in posterior 
portion and 0.8 to 1.5 mm. in region of spherical enlargement. Proboscis 
cylindrical, 0.5 to 0.6 mm. long by 0.07 to 0.2 mm. wide; armed with 
twenty-four to twenty-eight circular rows of hooks. Basal circle with 
twelve hooks; remaining circles with six hooks each; hooks in circles 
anterior to basal circle alternating: Smallest hooks at tip of proboscis, 
about 16 » long, with a diameter of 4 ». Largest hooks, in seventh or 
eighth circle from tip, 36 to 40 » long with a diameter of 22 ». Hooks 
posterior to the eighth row 20 to 36 » long with a diameter of 4 to 8 up. 
Roots on hooks of first eight circles back from tip of proboscis 10 to 40 w 
long. Embryos within body-cavity of gravid females 53 to 83 p long by 
8 to 13 w in diameter ; commonest size 63 by 10 pn. 
Hosts: Ictiobus urus, I. bubalus, Carpiodes carpio, Cyprinus carpio, 
Ameiurus nebulosus, A.melas, Pomoxis annularis, and P. sparoides. 
Intestine infested. 
RHADINORHYNCHUS Lthe, 1911 
Generic Diagnosis—Acanthocephala parasitic as adults in the intes- 
tine of fish. Anterior body-region armed with scattered cuticular spines, 
ensheathed by cuticular folds. Proboscis and proboscis receptacle very 
long. Ventral proboscis-hooks stronger than dorsal. Proboscis receptacle 
a two-walled muscular sac with the brain located near its middle. Lem- 
nisci long, finger-like. 
This genus is not strongly represented in American hosts either from 
the point of view of species or of numbers of individuals encountered in 
the examination of fishes. It is typically a marine genus which is probably 
occasionally brought into fresh-water by migratory fishes. 
RHADINORHYNCHUS.ORNATUS Van Cleave, 1918 
Proboscis armed with from twenty-two to twenty-four longitudinal 
rows of about forty hooks each. Hooks on proboscis 50 to 80 p long. 
Anterior body-region armed with scattered cuticular spines about 80 mu 
long. Embryos about 60 » long. 
Hosts, marine and migratory fishes. 
RHADINORITYNCHUS TENUICORNIS Van Cleave, 1918 
(Pl. XXIII, Fig. 9) 
Proboscis armed with ten to fourteen longitudinal rows of approx- 
imately twenty-six hooks each. Proboscis hooks of female 40 to 80 
long; those of male, near base, may be as short as 20 pw. Conspicuous 
crescent of about seven long spines on the ventral surface of the proboscis- 
