Herdmania pallida (Heller, 1878)

Fig. 4

Cynthia pallida Heller, 1878

Pyura (Rhabdocynthia) momus form pallida: Van Name 1921; Monniot C. 1983 and synonymy

Herdmania pallida: Monniot C. 2002, and synonymy; Nishikawa 2002 and synonymy; Rocha & Costa 2005.

Stations: AB: 102, 149, 175, 185, 187, 197, 354, 452. AD: 208, 259, 270, 277, 299. AM: 12, 22. AR: 55, 83, 91, 101, 114, 129, 143, 144, 186, 196, 364, 417, 459, 461, 465, 571. (MNHN S2 HER 99)

The round and soft bodies have a thick tunic often covered with epibionts. The dorsal side and the siphons are often red in life. The siphons are distant of 1/3 of the body length and their aperture shows blue and red iridescent colours and white spots (Fig. 4A,B). The dorsal tubercle is large with inrolled horns. The dorsal lamina has sharp languets. The branchial sac has an average of 9 high folds on the right side and sometimes there is a 10th incomplete fold, and a fold less on the left side. The hepatic gland is divided into 3 parts: 2 lobes on each side of the cardia and a larger lobe covering the pyloric side of the stomach (Fig. 4A). The gut loop is high and widely opened (Fig. 4A). There is one tubular and straight gonad on each body side (Fig. 4A). Oviduct and sperm duct open close to each other in simple holes. The anus has a smooth edge (Fig. 4B). There is a large velum at both siphon apertures. All tissues are filled with acicular spicules.

H. pallida was long confused with Herdmania momus . Full descriptions of this very common species have already been given by Van Name (1921), Monniot C. (1983) for Western Atlantic specimens, and other records from Indian or Pacific Oceans are in Nishikawa (2002), Monniot C. (2002) and Monniot F. & Debitus (2015).