| Diagnosis |
Large animals, grayish-yellow, dark yellow, or gray in color. Trunk of adult specimens 2- 6 cm long, elongated and spindle-shaped. Introvert 1.5-2 times longer than trunk. Surface of trunk smoothseeming, as papillae covering it small. Papillae pyriform or finger-shaped. Tentacular apparatus obviously subdivided into dorsal crown surrounding nuchal organ and crown of perioral tentacles. Dorsal crown consisting of 19-30 tentacles. Tentacles of perioral crown
arranged into pronounced parallel festoons running along cephalon. In each festoon, pair of anterior tentacles closest to mouth opening with common basal fold encircling bases of tentacles. In large specimens, sometimes up to 20-30 festoons, each bearing two rows of
12-20 tentacles. Violet or yellow circles visible around apical ends of tentacles. Longitudinal
musculature of body wall solid, not divided into longitudinal bands. Two retractors of introvert, both ventral, fastened in posterior third of body, close to ventral nerve cord. Contractile vessel of complicated structure, covered with finger-shaped tubercles of orange or yellow color. Gut long, number of intestinal loops 18- 54. Two fixing muscles fastening upper regions of ascending and descending loops of intestine. Anal opening located level with nephridiopores. No rectal diverticulum found. Two nephridia, free, not fastened to body wall, length about 30 percent of body length. |