PARASITES OF FISHES OF THE WOODS HOLE REGION. 
475 
4. Dirtomum ocreatum Molin. . Stomach. 7 , pp. 283, 288, pi. xxxv, figs. 16-24. See «►, pp. 514-515, 
pi. xlii, fig. 13. 
Microgadus tomcod, Tomcod. 
FOOD. 
Annelids, shrimp, amphipods, and other small crustaceans found in the alimentary canals. 
NEMATODES. 
1. Ascciris sp. [PI. ix, figs. 97-99.] Immature. Intestine. Found in July 1886, Aug. 1887, and 
1899; few. In intestine near pyloric creca; length, 25 to 35 mm; probably the young of Ascciris 
clavata. 
CESTODES. 
2. Larval cestodes (Scolex polymorphus Dujardin). Free in intestine. Aug. 2, 1900. See 4 , p. 789, etc. 
3. Rhynchobothrium imparispine Linton. Encysted on viscera. 4 , pp. 799-801, pi. lxiv, figs. 9-12. 
4. Rhynchobothrium sp. Encysted, submucosa of intestine and peritoneum. 4 , p. 794, pi. lxiii, fig. 2. 
TEEMATODES. 
5. Distornum appendiculatum Rudolphi. Intestine. Aug. 2, 1900. See 7 , p. 289, pi. xxxvi, figs. 25, 26. 
6. Distornum. simplex Bud ol phi . Intestine. [PI. xxx, figs. 331, 332.] ti, pp. 525-526, pi. xlvii, figs. 6, 7. 
Aug. 13, 1900; 3. 
These distomes when first seen were yellowish white, nearly transparent, the surface corrugated 
by fine transverse lines. They then resembled very closely the small distomes (No. 19 under P. dentatus 
[fig. 336] ) from the flounder collected August 17, 1899. When a specimen, which was quite short and 
corrugated and kept under slight pressure, was held over the flame of an alcohol lamp and warmed 
sufficiently to stiffen it, the body relaxed and became much elongated. After seeing the diverse shapes 
which distomes of the same species assume under different conditions of development and contraction 
one realizes the inadvisability of bestowing specific names on new forms in the absence of a good 
number of specimens. These specimens varied from 1.22 mm. to 2.47 mm. in length. A few 
dimensions of a specimen in glycerine given in millimeters are: Length, 2.40; breadth, 0.44; oral 
sucker, length 0.19, breadth 0.17; diameter of pharynx, 0.09; acetabulum, length 0.25, breadth 0.29; 
ova, 0.08 and 0.04 in the two principal diameters. 
Gadus callarias (Gcidus morrliua ) , Cod. 
ACANTHOCEPHALA. 
1. Echinorhynchus acus Rudolphi. 
Eleven lots in the National Museum collection from Woods Hole, collected in November and 
December, 1887; two in January, 1888, by Mr. Vinal N. Edwards; one collected August 22, 1883, 
and one from Eastport, Me. (Palmer, collector). Three of these lots contain very numerous specimens; 
the others range from 1 to 54. These specimens from the cod, while showing considerable variety in 
shape and size, agree closely in the maximum and minimum dimensions. The females in nearly every 
lot measure from 28 mm. to 30 mm. in length, and the males from 6 mm. to 8 mm. 
NEMATODES. 
2. A scar is clavata Rudolphi. Stomach. 
Eleven lots of nematodes from this host, seven collected at Woods Hole, by Vinal N. Edwards, 
in November, December, 1887, and January, 1888; one lot collected by Mr. Thomas Lee on the 
steamer Albatross, August 22, 1883; one from a salt cod, collected by Mr. A. IT. Clark; one from 
Long Island, collected by Mr. S. E. Meek, and one from Casco Bay, while presenting many individual 
variations, appear to belong to this species. The specimens in these lots vary from 6 mm. to 62 mm. 
in length. The smaller are relatively more slender than the larger ones, which were considerably 
thickened posteriorly. 
Dimensions of two specimens, in millimeters: Length, male 30, female 48; diameter of head, 
male 0.28, female 0.30; diameter 2 mm. back of head, male 0.80, female 0.70; diameter middle, male 
0.85, female 1.10; diameter 2 mm. from posterior end, male 0.80, female 1; diameter at anal aperture, 
male 0.25, female 0.35; distance of anal aperture from posterior end, male 0.15, female 0.28. 
