Polycarpa madagascariensis

Polycarpa madagascariensis Michaelsen, 1912

(Figures 30A, 31 A,B)

Polycarpa madagascariensis Michaelsen, 1912: 139, Madagascar, Nosy Be. Monniot C. 2002: 83 figs 4E-15-16 and synonymy and distribution.

Station. TA 41 (MNHN S1 POL.B 562). DW3530 (MNHN S1 POL.B 564).

Several specimens were dredge at 80m depth. A single specimen collected by SCUBA 5.5 x 3 cm is well preserved (Fig. 30A). Others are damaged, eviscerated, despite their strong and thick tunic. The oral siphon is apical; the atrial siphon is protruding at 2/3 of the body length. The tunic is clear, naked, with wide ridges and provided with basal roots of fixation. The body wall is thick, brown, prolonged into the basal roots. The oral tentacles are numerous. The dorsal tubercle opens in a C on the left side in a deep V of the peripharyngeal ring. The branchial tissue is thin (Fig. 31 B). All the transverse vessels are red. The 4 high folds do not recover each other. The formula on the right side is: E- 9- 17 -8- 20 - 9- 20 -7- 21 -2-DL.The rows of stigmata are narrow without parastigmatic vessels. The dorsal lamina progressively increases in height down to the oesophagus. The endostyle is linked to the body wall ventral line. The digestive loop is widely opened (Fig.31 A), the stomach is weakly linked to the body wall. It is narrow, has no obvious folds and no caecum and its limits with the oesophagus and the rectum are not distinct. The anus is lobed. The numerous oval polycarps are in a line posteriorly curved on each side of the body, they are pink in formalin. The gonad papillae are white. The internal side of the body wall is entirely covered with endocarps (Fig. 31 A) and the polycarps are hardly perceptible among them. The arrangement of the gonads and endocarps are the same in specimens with eviscerated gut. The atrial siphon lining is covered with filaments.

P. madagascariensis is known from Mozambique, Madagascar at Nosy Be, Mayotte and Mauritius.