446 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
2. Immature nematodes ( Ascaris ) . 
U. S. National Museum collection; U. S. Fish Commission, 1883. The label reads: “Side of 
bonito, external.” Length, 12 mm.; diameter, 0.26 mm. Posterior end acute, but truncate at tip. 
3. Ichthyonema sp. July 25, 1899. An Ichtliyonema, possibly more than one, in a tangled mass 
beneath the skin in gill cavity; flat and ribbon-like, with eggs, but no young in uterus. 
CESTODES. 
4. Larval cestode, on pyloric caeca. 7, pp. 278, 300, pi. xlii, fig. 100. Also see 4, p. 789, pi. lxi, 
figs. 2, 3. 
5. Larval cestodes (Scolex poly morphus Dujardin). Small. Free in intestine. Aug. 10, 1899; few. For 
account of these forms see 4, pp. 789-792. 
6. Rhynchobothrium. In cysts of stomach wall. 4, p. 795. July 31 and Aug. 9, 1899. 
7. Tetrarhynchus bicolor Bartels. 7 , p. 277. See 4 , pp. 813-815. 
8. Tetrarhynchus. Encysted in stomach wall. 7, p. 278. 
TREMATODES. 
9. Distomum vitellosum Linton. Intestine. See 7, p. 290, pi. xxxvri, figs. 38, 39. Aug. 23, 1900. 
10. Gasterostomum arcuatum Linton. 7, pp. 277-278, 297-298, pi. xli, ligs. 85-90. July 15, 1899; 
from four hosts, 18; from five hosts, 22. Aug. 10, 1899; from three hosts, several. Aug. 19, 
1899; 5. July 30, 1900; 36 from three fish. 
These occur most commonly in the pylorus, but were found in the stomach, pyloric caeca, and 
intestine. In one instance both young and adult were found together in the intestine. 
11. Hexacotyle tliynni De la Roche (?). [PI. xxvn, figs. 296-298.1 Aug. 7, 1900; 1, from mouth. 
Collected by Mr. R. P. Cowles. 
Dimensions in millimeters, specimen somewhat flattened: Length, 7.5; breadth of body, middle 
2, posterior 1.9, neck 0.55; length of neck, 0.94, the anterior tip tapering to 0.15 in a distance of 0.3; 
each of the six sucking disks 0.46 and 0.36 in the two principal diameters. 
Scomberomorus maculatus, Spanish Mackerel. 
FOOD. 
The stomachs of all the specimens which I have examined have been empty. The food habits 
are doubtless the same as those of the nearly related S. cavalla. 
NEMATODES. 
1. A.scaris incurva Rudolph! (?). Fragment, from intestine. July 30, 1900. 
A female with ova developing in uterus. Dimensions in millimeters: Length, 23; diameter, 1.75; 
diameter at anal aperture, 0.16; distance from anal aperture to posterior tip, 0.65. 
2. Ascaris clavata Rudolphi. Immature. From stomach. Collected by S. E. Meek, Fulton Market, 
New York, Aug. 30, 1886. Length of longest specimen, 40 mm. 
The bodies are rather thick, tapering somewhat quickly at anterior end, less so at posterior. 
One ala terminates on upper lip, the other on the left lower lip. In the larger specimen the vulva was 
situated 14 mm. from the anterior end. 
3. Immature nematode. Encapsuled on viscera. Aug. 13, 1889; fragment. Dimensions in millimeters: 
Length, 10; greatest diameter, 0.4; diameter at anal aperture, 0.13; distance of anal aperture 
from posterior tip, 0.45. Body crossed by fine lines, making sharply serrate outline. [PI. xiv, 
fig. 172.] 
4. Ichthyonema globiceps Rudolphi. From ovary. Collected by S. E. Meek, Oct., 1886. Fish from 
New Jersey coast. 
The specimens were first seen by me after they had been preserved in alcohol. They are imma- 
ture. The aggregate length of the fragments in the vial is 120 mm. These represent two specimens. 
The diameter is uniform throughout and is about 0. 18 mm. 
