Ascidians from the tropical western Pacific Author Monniot, Françoise Author Monniot, Claude UPESA 8044, Laboratoire de Biologie des Invertébrés marins et Malacologie, Muséum national d’Histoire naturelle, 55 rue Buffon, F- 75005 Paris (France) monniot @ mnhn. fr. monniot@mnhn.fr text Zoosystema 2001 23 2 201 383 journal article 10.5281/zenodo.5391440 1638-9387 5391440 Diplosoma marsupiale n. sp. ( Figs 60 ; 121D ) TYPE MATERIAL . — Philippines . Bohol Sea, Camiguin Island, 9°12.89’N , 124°38.03’E , 4 m , 18.IV.1997 ( MNHN A 2 DIP . A 148). ETYMOLOGY. — From the Latin marsupium : pouch. DESCRIPTION The colonies extend in thin whitish sheets on a sandy bottom. The thin and soft tunic is colourless, most transparent at the edge of the colony and between the groups of zooids. It contains a white pigment around the zooids ( Fig. 121D ). The basal layer includes sediment particles. Brown pigment cells make a peculiar design in the body wall of the zooids. There are six radiating lines around the base of the oral siphon, a speck with a diffuse outline at the anterior end of the endostyle, and a spot at the anterior edge of the cloacal aperture. In addition, there is a brown pigmentation on the gut and gonads. The oral siphon has six large, petal-like lobes above a strong sphincter ( Fig. 60A ). The cloacal opening is wide. The branchial sac has 10 elongated stigmata on each side in the first row. The retractor muscle is shorter than the thorax, and issues from the posterior part of the thorax ( Fig. 60A ). The abdomen is folded under the thorax. The two testis lobes ( Fig. 60B ) are pressed against each other and against the gut loop. The ovary has the usual place against the testis. The eggs remain in the abdomen, and even advanced larvae with a developed tail and buds remain includ- ed in the abdomen against the digestive loop. The larvae ( Fig. 60C ) measure 0.75 mm for the trunk. They are made opaque by an abundance of round white cells distributed throughout the larval body wall except at the base of the tail and the tip of the adhesive papillae. The adhesive papillae have narrow brown stems. They are encircled by eight or more often 10 short ampullae. REMARKS This species has some characters in common with Diplosoma versicolor Monniot F., 1994 : brown pigment, large oral lobes, a retractor muscle, and two testis lobes. It differs in the shape of the colony, and the size and internal structure of the larva.