Prostoma bipeltatum

Kajihara, Hiroshi, 2025, A taxonomic revision of the freshwater monostiliferous hoplonemertean genus Prostoma Dugès, 1828 (Nemertea: Eumonostilifera): a radical solution or an over-lumping?, Zootaxa 5646 (4), pp. 451-500 : 488

9. Prostoma bipeltatum

(Annex Fig. 1H)

Description. Very small nemertean, up to 8 mm in length. Body thin, round, gradually tapering slightly towards both ends. Alimentary canal delicate pink, transparent, visible through carmine-red colour [of basement body?]. Large, brown cephalic patch behind anterior pair of eyes. Shiny white anal glands with same shape as cephalic patch present at posterior end of the body is a. In front and behind the head pigment spot, there is an accumulation of white, glandular cells. Rather bright, orange-yellow mid-dorsal stripe, formed by epidermal pigments, running for entire body.

Locality. Stones with bryozoans, 50 m deep (Annex Fig. 2 , XXIII), 5 specimens .

Remarks. The original figure (рис. 8) shows two accessory stylet pouches, each containing two or three accessory stylets; now Tetrastemma bipeltatum ( Timofeev, 1911) .

Figures

FIGURE 2. Prostoma clepsinoides Dugès, 1828 from Lake Biwa, Japan. A, Entire specimen in living state, lost after photographed. B, C, Transverse sections through proboscis anterior chamber; white arrowheads pointing to proboscis nerves. D, Sagittal section through the opening of the oesophagus–rhynchodaeum complex; black arrowheads pointing to cilia on ventral wall of oesophagus; anterior to the left. E, Magnification of D, showing sparse cilia on ventral wall of oesophagus, indicated by black arrowheads. F, Magnification of D; black arrowhead pointing to longitudinal muscle fibre along rhynchodaeum.G, Sagittal section near rhynchodaeal opening; anterior to the right. B, D, E, F, ICHUM 6272; C, ICHUM 6277; G, ICHUM 6273.