Marionina clavata Nielsen & Christensen, 1961

(Figure 18)

Material examined. 5 specimens (three were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000866133, NIBRIV0000866134, NIBRIV0000837805, in 70 % ethanol) .

Our observations mostly agree with the description of Nielsen & Christensen (1961). Small worms (4–7 mm long, 280–330 μm wide at XII in vivo), segments 22–27. Chaetae straight, maximum 2 per bundle, absent laterally in VIII–XII (but in the original description in IX–XII). Clitellum saddle-shaped, gland cells pattern irregular (Fig. 18A), glands absent midventrally (Fig. 18B). Brain incised posteriorly. A pair of short, club-shaped, hollow oesophageal appendages present dorso-laterally in IV (Figs 18 C–E). All pharyngeal glands connected dorsally (Fig. 18C). Dorsal blood vessel origin in XII, anterior bifurcation in I. Coelomocytes oval, 25–28 μm long, finely granulated. Two pairs of preclitellar nephridia at 7/8–8/9, with considerable anteseptale, postseptale with gradual transition into terminal efferent duct (Fig. 18F). Sperm funnels (Fig. 18G) and penial bulbs small (Fig. 18B). Spermathecae possess long ental ducts covered with small glands all along. Ampullae pear-shaped, ental ducts united dorsally and communicating with oesophagus (Figs 18H, I).

Distribution and habitat in Korea. Mt. Odaesan, Sangwonsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers, Abies holophylla forest, N 37°47’09.03”, E 128°33’42.75”, 969 m asl; Mt. Jumbong, near to Hangyeryong, Inje-gun, Gangwon-do, soil and litter layers of Q. mongolica forest, N 38°05’17.33”, E 128°23’12.49”, 659 m asl.