Note 4 — Third Sub-Kingdom: VERMES (Worms).

227Fig. 134.—The Beet Eelworm (Heterodera Schachtii): 1, A beet root with adult females attached (natural size); 2, a lateral rootlet of beet which Eelworm larvæ (a) are penetrating (enlarged); 3, a lateral rootlet of beet with swelling (a) of the outer skin caused by the excessive development of larvæ which have previously entered it, and which have now become nearly mature females (enlarged); 4, a just-hatched larva; 5, a larva which has penetrated a root and swollen up into a club-shaped form; 6–8, development of the male; 9, a nearly adult and, 10, an adult female. The following letters have reference to Figs. 4–10: a, mouth spine,—b, sucking stomach (pharynx),—c, d, intestine,—e, f, rectum,—f, anus,—g, excretory organ; h (in Figs. 4–7), rudiments of the sexual organs in the undeveloped larvæ; h (in Fig. 8), testis; i (in Figs. 7 and 8), copulatory spicules of the male; k (Figs. 9 and 10), ovary; l (Figs. 9 and 10), female sexual opening; m, nerve ring; w1 (Figs. 6–8), larval skin; w2 (Figs. 6–8), new skin which the developing male forms within the larval skin. Figs. 4 and 5 are magnified more than Figs. 6–10.