OCR Text |
Show 1 9 0 4 .] FROM EAST AFRICA AND ZANZIBAR. 2 9 1 S t il ig er ir r e g u l a r is , sp. n. (Plate XVII. fig. 12.) Two specimens from Chuaka on the East Coast of Zanzibar, found among Sertularians. The animal had a somewhat peculiar appearance owing to the hinder cerata being about twice as long as those in front and spreading out in a fan-like shape. One specimen was of a translucent white, but the liver, extending in two lines down the side of the body and giving off branches to the cerata, was green, and created an impression that the whole animal was of that colour. In the other specimen the branches of the liver in the cerata were of a dirty yellow, and there was some reddish-grey pigment in the integuments of the body, so that the longitudinal liver-tubes were not easily discernible. Near the head, however, they were distinct and green. The cerata in this specimen had white spots. The animals were less than 2 mm. long. Only one specimen has been preserved, and its very small dimensions rendered examination rather difficult. In the hinder part of the body there are two longitudinal lines of cerata arranged in five transverse rows on each side, of which the inner are two or three times as long as the outer. In the front part there is a single line of five small cerata, and there are no signs of others having been detached. The cerata are cylindrical, much like those of Hermcea dendritica, and not inflated or ovate. Though the surface of the liver-branches is irregular, they do not appear to have distinct secondary ramifications within the cerata. No pericardial prominence is visible. The rhinophores are short and simple; behind them are two very distinct black eyes. The oral veil is circular and not notched. The foot is truncate in front; there were no signs of a groove or tentacular prolongations of the corners. The radula consists of four teeth in the ascending portion, six in the descending, and a small heap. The teeth are much like those of S. varians, but the outline is somewhat simpler and less wavy (PI. XVII. fig. 12). P H Y L L O B R A N C H ID i:. [Bergh, in S. R. ii. & xvi.; id. Beitrage zur Kennt. d. Aeoli-diaden, ix .; A. & H., Coll. of Nudibr. Moll, made in India, p. 145 ; Trinchese, Aeolididse del Porto di Genova, 1881 ; Pelseneer, Re-clierches sur divers Opisthobranches, 1894, pp. 50-52.] This remarkable family, which is characterised by its flat leaflike dorsal papilla?, consists of three genera, Phyllobranchus, Cyerce, and Caliphylla, of which the first two are recorded from the Indo-Pacific (but Ph. viridis from the West Indies), and the last from the Mediterranean. They all agree in having flat leaf-like cerata, an ascoglossan radula and a buccal crop, complicated reproductive organs, and (except Caliphylla) oral tentacles as well as rhinophores. Cyerce, though very like Phyllobranchus 19* |