482 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Dimensions of living worm in millimeters: Length, 4; distance of genital aperture from anterior 
end, 2.3; length of oesophagus, 0.65; diameter of head 0.23, at genital aperture 0.38, two-tenths of a 
millimeter in front of the anal aperture 0.25, at anal aperture 0.09; distance of anal aperture from 
posterior end, 0.11. 
7. Ichthyonema sanguineum Rudolphi. Mouth. 7 , pp. 283, 304, pi. xliii, figs. 120, 121. 
CESTODES. 
8. Larval cestodes (Scolex polymorphus Dujardin) . In cystic duct and free in intestine. 4 , pp. 789-792, 
pi. lxi, figs. 4-15. 7 , p. 283. 
Found frequently in 1899 and 1900. I have not been making observations on these forms ( Scolex 
polymorphus) for a good many years. I have recorded their occurrence, however, whenever observed. 
No doubt if special search were made for them their known range in American fishes could be greatly 
extended. On August 23, 1900, I noted these larvae in the flounder, and found among them forms 
with a very distinct costa on the bothrium. Red pigment spots were present in the neck, and the 
terminal sucker was conspicuous. While I was watching them I noticed lhat four had attached 
themselves to the scolex of a tetrarhynclius, which was in the same dish, thus becoming ecto-parasites, 
or carnivorous enemies of the latter. 
9. Rhynchobothrium bulbifer Linton. Cysts on viscera. 
Larval cestodes encysted in the mesentery are very common, and have been noted on various 
occasions. Many of them have been too immature for identification. Noted on six dates in 1899 and 
on four in 1900. 4 , p. 767. 7 , p. 283. Some of these small cysts contained larvae with proboscides 
resembling those figured in 4 , pi. lxiii, fig. 12. 
10. Rhynchobothrium imparispine Linton. On viscera. 4 , pp. 799-801, pi. lxiv, figs. 9-12. 
11. Rhynchobothrium heterospine Linton. On viscera. 7 , p. 283. See 4 , p. 799, pi. lxiv, figs. 3-8. 
12. Rhynchobothrium speciosum Linton, (hi viscera. 4 , pp. 801-805, id. lxiv, figs. 13,14, and pi. 
lxv, figs. 1-7. 
13. Tetrarhynclius bisidcatus Linton. In submucosa of stomach. 4 , pp. 810-811, pi. lxvi, figs. 11-15. 
7, p. 283. 
Cysts with larvae ( Tetrarhynclius ) found very frequently in submucosa of stomach in 1899 and 
1900. Some appear to be T. robustus ( 4 , p. 452), but the most of them are T. bisulcatus. 
14. Tetrarhynclius bicolor Bartels. 
A single specimen, August 15, 1899, in material washed out of alimentary canal. Color, white. 
In other particulars it agrees with this species; length, 3.5 mm. See 4 , pp. 813-815, pi. Lxvnr, 
figs. 1-6. 
15. Synbothrium filicolle Linton. Encysted in stomach wall. 4 , p. 817, pi. lxviii, fig. 8. 
TREMATODES. 
16. Dididophdsrh affinis Linton. \Octoplectanum affine Linton.] Mouth. 4 , pp. 511-512, pi. xl, figs. 
10-13, and pi. xli, figs. 1-5. Found twice in 1899 and once in 1900, one in each find. 
17. Dislomum appendiculcitum Rudolphi. Intestine. 7 , pp. 283, 289, pi. xxxvi, figs. 25, 26. July 
15, 1899; 2. 
18. Dislomum monticellii Linton. Intestine. Aug. 18, 1899; 1. See 4 , pp. 518-520, pi. xliv, figs. 2-8. 
19. Distomum vitellosurn Linton. Intestine. Aug. 23, 1899. July 26, 1900, few. See 7, p. 290, pi. 
xxxvii, figs. 38, 39. 
Two small distomes were obtained from a flounder from Muskeget Channel, August 17, 1899, 
which resemble this species in the general arrangement of the reproductive organs and proportions of 
the acetabula, etc. The bodies, however, were transversely corrugated in a very peculiar manner. 
This has been alluded to under Microgctdus (No. 6, D. simplex). The posterior edge of the acetabulum 
was deeply notched so as to form two or three blunt, digitate lobes. [PI. xxx, fig. 336.] 
20. Distomum pudens Linton. 7 , pp. 283, 290-291, pi. xxxvii, figs. 40-47. 
21. Distomum sp. [PI. xxxi, lig. 345, pi. xxxii, fig. 352.] 
Three small distomes collected August 22, 1899, are here referred to briefly. They bear a close 
resemblance to No. 11 under Rhombus triacanthus. One of these was sketched at the time of collecting 
(fig. 352). This specimen bears some resemblance to D. pudens, but the oesophagus is much longer 
