Teratocephalus lirellus Anderson, 1969

(Fig. 6 F)

Dimensions of 30 females: L = 0.37 -0.54 mm; a = 31-43; b = 4.1-5.6; c = 2.3 - 3.5; V = 9" 1839- 50.

Body slender, curved ventrad in death, most strongly in the anal region, whereas the distal part of the tail in many specimens curves to dorsal side. Transverse striae of cuticle 1.3 -1.4 \x apart. Lateral field distinctly demarcated, ending at level of intestine-rectum junction. Lip region offset by constriction, about 8 \x wide and 5 [ ihigh; width of neck immediately behind it about 6 [j,. Cheilorhabdions rather long and thin. Oesophagus of uniform thickness till the oval terminal bulb which occupies one-eighth to one-ninth of its length. Nerve ring and excretory pore about middle of neck. Gonad with only few oocytes; no sperm; a structure resembling an empty spermatheca is present at the flexure. Rectum twice anal body width long. Tail filiform, distally curved into half a circle or more, usually dorsolaterad; its length equal to 19-35 anal body diameters. Vulva inconspicuous; a short postvulval sac is present.

This species is extremely widespread on Spitzbergen; it was found in samples 2, 3, 6, 8, 11, 15, 16, 17, 20, 21, 23, 24, 25, 27, 28, 29, 31, 33, 35, 37, 39, 40, 41, 43, 44, 46, 47, 48, 49, 53, 54, 55, 56, 57/58, 60, 61, 62, 64, 65 and 66.

The very long tail and pre-equatorial vulva immediately distinguish this species from T.terrestris (Biitschli, 1873), (cf. Fig. 6 D-E).