Fig. 315.—Hæmonchus contortus: vulval region of female viewed from left side. int., intestine; lab., linguiform process covering vulva; ov., ovary; ovij., ovejector; ut., uterus; vag., vagina; vul., vulva. × 75. (After Ransom.)
Small mouth cavity contains a “tooth” or “lancet” arising from the dorsal side. Cuticle of head and neck not inflated. Cervical papillæ well marked. Bursa bilateral, with large lateral lobes and a small dorsal lobe not median, but lateral, attached to the base of one of the lateral lobes (fig. 316). Posterior ray bifurcate, each branch bifid apically. Each lateral lobe six rays. Anterior rays separated distally, curving forward. Antero-median and postero-median rays distally curve away from the antero-external. Postero-external ray long and slender. Spicules less than 1 mm. Gubernaculum present. Vulva in posterior part of body covered by a prominent tongue-like flap. Eggs ellipsoidal.
Hæmonchus contortus, Rudolphi, 1803; Cobb., 1898.
Dorsal “tooth” or “lancet” 10 µ to 15 µ long. Cervical papillæ 0·3 mm. from head.
Male 20 mm. long by 400 µ thick (maximum). Asymmetrical lobe of bursa 150 µ by 125 µ attached to left lateral lobe. Posterior ray bifurcate; each branch bifid. Stem of ray less than twice as long as its branches. Spicules 300 µ to 500 µ with knobbed tips, and the left spicule with a barb 20 µ from the tip, right spicule with a barb 40 µ from tip. Gubernaculum 200 µ by 25 µ to 35 µ, fusiform with thickened edges.
Fig. 316.—Hæmonchus contortus: tail of male, dorsal view, d., posterior ray of the asymmetrically placed posterior lobe; e.d., postero-external; p.l., postero-median; m.l., antero-median; e.l., antero-external; l.v., latero-anterior; v.v., antero-anterior; gub., gubernaculum; sp., spicule. × 75. (After Ransom.)
Female 18 to 30 mm. by 500 µ (maximum). Vulva 3 to 4·5 mm. from tip. Linguiform flap 0·5 mm. (a second one exists, according to Brumpt). Anus 400 µ to 630 µ from tip. Tail acutely pointed. Eggs 75 µ to 95 µ by 40 µ to 50 µ.
Habitat.—Fourth stomach of cattle, sheep, antelope.