Family. Dracunculidæ, Leiper, 1912.
Genus. Dracunculus, Kniphoff, 1759.
Anterior end rounded with a cuticular thickening or shield. Mouth triangular with two lips. Alimentary canal atrophied.
Dracunculus medinensis, Velsch, 1674.
Syn.: Vena medinensis, Velsch, 1674; Dracunculus persarum, Kämpfer, 1694; Gordius medinensis, Linné, 1758; Filaria dracunculus, Bremser, 1819; Filaria æthiopica, Valenciennes, 1856; Dracunculus medinensis, Cobbold, 1864; Guinea worm, Medina worm.
Fig. 276.—Guinea worm (Dracunculus medinensis). (After Leuckart.)
The females attain a length of 50 to 80 cm., or even more, and average 1·5 to 1·7 mm. in diameter. They are whitish or yellowish in colour. The anterior extremity is roundish and bears a cuticular thickening or shield. The triangular mouth opening is surrounded by two projections or lips, behind which on the shield there are two lateral and four sub-median papillæ; the posterior end terminates in a spine, ventrally directed, and about 1 mm. in length; the alimentary canal below the œsophagus is atrophied, but not entirely obliterated; anus absent; the lateral lines are very flat. The greater part of the body is occupied by the long uterus, in which a great number of young larvæ are always found. The ovaries probably lie at the ends of the uterus; the vulva lies just behind the cephalic shield. During parturition the uterus is prolapsed through this opening.