Family. Gnathostomidæ.
Genus. Gnathostoma, Owen, 1836.
Syn.: Cheiracanthus, Diesing, 1839.
Easily recognizable by the numerous spines which cover the entire body or only the anterior extremity, and terminate in several points; head globular and beset with bristles; mouth with two lips; two spicules; vulva situated behind the middle of the body.
Gnathostoma siamense, Levinsen, 1889.
Syn.: Cheiracanthus siamense, Lev., 1889.
Fig. 275.—Gnathostoma siamense: to the left, the entire worm (8/1); to the right the head seen from above, with two fleshy lips (about 40/1). (After Levinsen.)
Female measures 9 mm. in length, 1 mm. in breadth. There are eight rows of simple spines on the head; the armature of spines extends over the anterior third of the body only; each spine on the anterior region of the body spreads into three points, of which the middle one is the longest; the posterior spines are simple; they gradually become smaller and then disappear entirely. The vulva is situated behind the middle of the body.