Fridericia sphaericoides

Description. Holotype 18.4 mm long, 340 µm wide at VIII and 410 µm at clitellum in vivo (10.3 mm long, 380 µm wide at VIII and 390 µm at clitellum, fixed), segments 52. Body length of paratypes 14 – 20.5 mm, width 320 – 420 µm at VIII and 350 – 480 µm at clitellum, in vivo, length of fixed specimens 7 – 12 mm, width 370 – 480 µm at VIII and at clitellum, 350 – 520 µm, segments 47 – 61. Chaetal formula: (2) 3,4 – 4,2: 4 – 4,3,2. In one case (slide No. 2938) in segment X, 5 chaetae occur in one bundle. As in other Fridericia species, chaetae within a bundle arranged in pairs, outer longer and thicker than inner (45 – 55 × 4 – 5 μm vs. 22 – 32 × 3 – 4 μm, preclitellar bundles). Lengths of chaetae in postclitellar segments about the same as larger outer chaetae in preclitellar bundles. Two chaetae per bundle from about XXI – XXVII; chaetae gradually increasing in size posteriad from 52 × 5 μm to 62 – 70 × 5 μm in terminal segments. Head pore at 0 / I. Dorsal pores from VII. Brownish epidermal gland cells arranged in 2 – 3 transverse rows per segments (Fig. 6 F). Clitellum in XII – 1 / 3 XIII, girdle-shaped, hyalocytes and granulocytes arranged in dense rows dorsally (Figs 6 B – C), in the ventral midline before and about the half part of the male copulatory organs only granulocytes (Fig. 6 D). After fixation, body diameter of body narrowed at clitellum (Fig. 6 E). Body wall thick, 40 – 58 µm, cuticle 1 – 3 µm, fixed. Brain egg-shaped (Fig. 6 A), 110 – 150 μm long, when fixed, 1.2 – 2 times longer than wide. Oesophageal appendages (Fig. 6 G) with few short branches at forepart and at the end. Pharyngeal glands usually united dorsally, in IV widely connected, in V and VI connection may be narrow or absent; all with ventral lobes, small in IV, longest in VI (Fig. 6 H). Chloragocytes from V. Dorsal vessel from XVIII – XXI, blood colourless. Midgut pars tumida not seen. Five pairs of preclitellar nephridia (Fig. 6 K) from 6 / 7 to 10 / 11; length ratio anteseptale: postseptale 1: 1.7, midventral or subterminal origin of efferent duct. Coelomo-mucocytes elliptical with fine refractile granules at cell periphery, type b, length mostly 32 – 50 µm (Fig. 6 I – J), aggregations opaque with dark tint, lenticytes small and scarce (4 – 10 μm long, in vivo). Chylus cells between XIV – XVI, occupying 2 – 3 segments. Seminal vesicle large (X – XI). Sperm funnels cylindrical (Figs 6 L – M, 7 A), 250 – 390 µm long, in vivo and 2 – 4 times as long as wide (180 – 360 µm long and 1.7 – 2.7 times as long as wide when fixed). Collar slightly narrower than funnel body. Spermatozoa long, length 250 – 410 µm, heads 90 – 140 µm, in vivo. Diameter of sperm ducts about 10 µm. Male copulatory organs (Fig. 7 B) 100 – 300 µm long, 80 – 200 µm wide and 50 – 60 μm high, in vivo (105 – 150, 78 – 100 and 30 – 65 µm fixed, respectively), bursa conspicuous, the laterally bent bursal slits are longitudinal. No subneural glands. Ectal ducts of spermathecae long, length 390 – 420 µm and width 20 – 30 µm, in vivo (250 – 380 µm long, and 18 – 24 µm wide, fixed), no ectal glands (Fig. 7 C – G). Ampullae large, onion-shaped, without diverticula, diameter 90 – 116 µm in vivo (fixed 67 – 115 µm), ental bulbs (60 – 80 µm wide, in vivo) projecting into lumina of ampullae, sperm in a circle around the bulb (Figs 2, 7 D – E). Ectal duct canal 3 – 6 µm wide, straight inside the ental bulb, without spiral loops. Distal and proximal parts of ampullae considerably set off by a constriction, the proximal part about 60 – 90 µm long, fixed, separate openings into oesophagus. 2 – 4 mature eggs at a time.