Phallusia

Station: AB 159 (MNHN P 5 PHA 127) A specimen 5 cm long has an ovoid shape with a very smooth stiff colourless tunic. It was attached by its whole ventral side. The oral siphon is apical. The atrial siphon is slightly protruding at 1 / 2 of the body length its aperture directed anteriorly. Internal organs are not pigmented (Fig 13). All anatomical characters are the same as those described for P. nigra collected from the nearby stations. The prepharyngeal area is narrow with papillae (Fig. 15 A). The dorsal tubercle opens in a small C. The neural ganglion and the neural gland are close to the base of the atrial siphon (Fig 15 B). The duct of the neural gland has numerous apertures along its whole length (Fig. 14 A; 15 B, C). The branchial sac (Fig. 14 B) has round papillae some of them with a basal extension. A line of long pointed papillae extends on the right side of the oesophageal aperture (Fig. 14 B). The gut in a double loop has no inflated rectal pouch (Fig; 13; 14 A). The musculature (Fig. 14 A) has exactly the same design as that described for P. nigra. This ascidian may be an albino specimen as even in formalin P. nigra keeps its deep black colour even stored in formalin during many years.