PARASITES OF FISHES OF THE WOODS HOLE REGION. 
425 
SUMMARY OF FISH PARASITES ARRANGED UNDER THEIR HOSTS. 
Mustelus canis, Smooth Dog-fish. 
FOOD. 
The alimentary canals usually contain crabs [Panopens, Platyonichus, Cancer, Lihinia, etc..). Squid, 
annelids, and fish have also been noted. 
NEMATODES. 
1. Ascaris sp. [PI. ix, fig. 90.] 
Two imperfect specimens in U. S. National Museum collection apparently removed from peritoneal 
capsules. Dimensions in millimeters: Length, 23; diameter of head, 0.12; maximum diameter a little 
back of middle, 0.45; distance of anal aperture from posterior end, 0.15. Head with three short lips, 
two bluntly angled, the third rounded. Body transversely rugose; posterior end bluntly rounded 
with a mucronate tip which is conical and wrinkled. 
CESTODES. 
2. Dibothriuvi sp. Spiral valve. 5, p. 433. 
3. Calliobothrium verlicillaturn Rudolphi. Spiral valve. 1 , pp. 476-479, pi. iv, figs. 1-8. 2, pp. 810-812. 
5, p. 447, pi. xxxiv, figs. 6, 7. 7 , p. 270. Aug. 14, 1899; from two hosts, 25 large, 9 small. 
Aug. 28, 1899; from one host, 8. July 18, 1900; from one host, 63. 
Ripe proglottides noticed on one occasion- upon which apertures for discharge of ova had devel- 
oped. These were arranged along the median line of one of the flat surfaces and numbered about five 
in most cases, although as many as eight were counted. When the proglottis was viewed from the 
margin these apertures were seen to be slightly projecting. [FI. xxvi, fig. 289, a and 5.] 
4. Calliobothrium eschrichtii Beneden. Spiral valve. 2, pp. 812-816, pi. vii, figs. 5-12. 5, p. 447. Aug. 
14, 1899, 1. 
5. Rhynchobothrium lomentaceum Diesing. Spiral valve. 2, pp. 845-847, pi. xm, figs. 1-3. 
6. Rynchobothrium bulbifer Linton. Spiral valve. 1 [77. tenuicolle Rudolphi], pp. 486-488, pi. v, figs. 
17, 18. 2, pp. 825-829, pi. x, figs. 8, 9, and pi. xi, figs. 1, 2. 5, p. 448. 7, p. 270. July 26, 
1899; from two hosts, 22. Aug. 14, 1899; from two hosts, 12. Aug. 28, 1899; from one host, 3. 
7. Rhynchobothrium tumidulum Linton. Spiral valve. 2, pp. 829-832, pi. xi, figs, 3-11. 5, p. 448. 7, 
p. 270. July 18, 1900; from one host, 6. 
8. Rhynchobothrium heterospine Linton. Spiral valve. 2, pp. 839-840, pi. xii, figs. 3-5. 
9. Rhynchobothrium sp. Blastocyst, stomach. 4, p. 798, pi. lxiv, fig. 2. 
10. Tetrarhynchus sp. Cysts, stomach-wall. 4, p. 809, pi. lxvi, figs. 6, 7. 
11. Synbothrium filicolte Li nton. Cysts, stomach-wall. 4, pp. 815, 819, 820, pi. lxviii, fig. 9. 
Galeocerdo tigrinus ( Galeocerdo maculalus ), Tiger Shark. 
food . 
The stomach may contain a great variety of objects ( 7, pp. 270-271), but fish, univalve mollusks, 
and squid probably constitute the principal food. The single specimen examined in 1899 had been 
kept in confinement for two or three weeks and had nothing in the alimentary canal except two 
opercula of the winkle ( Sycotypus canaliculatus) , feathers of a flicker, and some green seaweed in the 
intestine. In the specimens examined in 1887 fragments of menhaden, bonito, and opercula of the 
winkle were noted. 
NEMATODES. 
1. Ascaris breidcapitata spnov. ; stomach. [PI. hi, figs. 19-22.] 
Four specimens collected August 3, 1889, and a single specimen belonging to the National 
Museum collection are of nearly uniform diameter for the greater part of their length, but are 
attenuate anteriorly, particularly so for about 5 mm. at the anterior end; greatest diameter near 
posterior end, which is recurved. Longest female 102 mm. in length and 1 mm. in diameter; body 
marked with regular annulations about 0.008 mm. in length; oesophagus linear; spicules of male long 
and slender; about 8 postanal and 30 or more preanal papilla: on each side; jaws very short and pro- 
vided with papillae. Dimensions of a male in millimeters: Length, 70; diameter of head, 0.17; length 
of head, 0.08; diameter of body one mm. back of head 0.56, one mm. from posterior end 0.75, at anal 
aperture 0.37, maximum diameter 1.25; distance of anal aperture from posterior end, 0.51. 
