Corella minuta

Station. CP 4383. Only one specimen 2 cm in length was collected at 83 m depth. The tunic is vitreous and totally transparent but solid. The body was erect above a sandy base. The long atrial siphon is apical with 6 very short lobes, it has no muscular sphincter but a few circular muscular fibres (Fig. 15 A, B) apparently representing an extension of the body musculature The oral siphon is short with an undulated rim. The body musculature is unique in this genus. In addition to the 5 strong transverse fibres issued from the dorsal side which encircle the atrial siphon and extend on the dorsal body side, few very thin fibres lie at the base of the oral aperture and two thick short ribbons are placed in the middle of each body side (Fig. 15 A, B). The dorsal tubercle opens anteriorly in a C. Thirty-two oral tentacles alternate in 2 sizes. The branchial sac is flat. Thirty longitudinal vessels were counted on each side. The stigmata are grouped 4 by 4, each with 2.5 not interrupted turns (Fig. 15 C). Twenty-two triangular rapheal languets become alternatively long and short near the oesophagus entrance. The gut forms a closed loop at the posterior part of the body prolonged along the dorsal line by a long rectum. The oesophagus is short giving into an olive-shaped stomach with 6 low folds on each side. The rectum ends at the base of the atrial siphon in a scalloped rim. The testis is ramified and spread over the whole intestinal loop mixed with the ovary. All characters of this ascidian well correspond to those of Caribbean specimens collected several times by several authors (Monniot C. 1983 a). More surprising are the records of this species in New Caledonia, Polynesia and Mozambique (Monniot C. 1997 and synonymy). The origin of this discrete but widely distributed species is unknown.