Halocynthia spinosa

Halocynthia spinosa Sluiter, 1905

(Figure 33)

Halocynthia spinosa Sluiter, 1905: 16 pl. 2 fig. 8, Djibouti. Monniot & al 2001: 116 figs 55C–F and synonymy. Monniot C. 2002:108, Israel, Yemen, Mozambique.

Station. TA 41 (MNHN S2 HAL 53)

The single specimen 3cm large is covered with epibionts. The tunic is bristling with spiny papillae (Monniot & al 2001 fig. 55C–F). The body wall musculature is made of crossed transverse and longitudinal ribbons. On each side the 12 branchial folds recover each other (Fig. 33 A); they have about 28 longitudinal vessels ending in long papillae near the oesophagus. On each side of the endostyle the first fold is not complete. The straight stigmata are cut by parastigmatic vessels. The digestive tract occupies the most part of the left body side (Fig. 33 B). The oesophagus is long. The stomach begins by a wide cardia with longitudinal folds (Fig. 33 B) and the pyloric part is covered by the hepatic gland. The intestine curves to join the oesophagus in a secondary loop. The edge of the anus is simple. The ovary in 2 lobes is located inside the gut loop against the body wall. The testis vesicles are spread internally over the ovary and the intestine. The female papillae are protruding; they are sided by a male papilla and take place on the rectum at the level of the secondary intestinal loop. Numerous endocarps are present.

The geographic distribution of H. spinosa extends along the western coasts of the Indian Ocean from the Red Sea to South Africa.