OCR Text |
Show 1903.] FROM EAST AFRICA AND ZANZIBAR. 361 Trippa.-Soft, and sometimes spongy or gelatinous. The back is covered with tubercles which themselves bear smaller prominences or filaments. A labial armature is occasionally present (Section Fracassa). Some species have special glands set round the buccal mass, and the sides of the head connected with the foot, but it does not appear to m e that the absence of these characters ought to exclude a form from the group. Halgerda.-The texture is entirely smooth and somewhat stiff, though ridges may be present. In the known species the branchiae are scanty. No member of this group is known to possess a labial armature. Kentrodoris.-Broad, soft, and flat, with the dorsal surface minutely granulated. The broad foot is deeply grooved in front, and the upper lip, which is notched in the middle, is developed into wing-like expansions on each side. The reproductive system is sometimes armed, and accessory organs are present. In some species, at any rate, the branchiae are unusually large. Platydoris.-Very flat forms, of a peculiar hard consistency. The back is minutely granulated and rough to the touch. The foot is narrow. The branchial pocket is stellate in the known forms. A labial armature is rare {PI. variegata). There is a characteristic genital armature of scales bearing hooks. Asteronotus.-Of a characteristic leathery consistency. The back is quite smooth in texture, but bears lumps and ridges. No labial or genital armature. Sclerodoris.-This new genus is proposed for certain forms which appear to have never come into the hands of Prof. Bergh, though I think Alder & Hancock's Doris osseosa, carinata, apicu-lata, and tristis (" Notes on a Collection of Nudibr. Moll, made in India," Trans. Z, S. vol. iii. 1864) should be referred to this genus. It is characterised by having the same hard texture as Platydoris, but the back, instead of being smooth, is marked with various ridges and depressions. In the known species there is no labial or genital armature. I should wish to bring m y Sclerodoris under Prof. Bergh's Dictyodoris, but the generic characters as formulated by him do not include the hard texture and raised reticulate pattern. Of the above-named genera, Asteronotus and Kentrodoris, though well characterised and not rare, have not hitherto proved numerous in species. 1. ARCHIDORIS AFRICANA, sp. n. One specimen marked " Chuaka, shore." No notes as to living animal. Alcoholic specimen 5 centimetres long, 1'6 high, with a fairly uniform breadth of 2'7, plump and not flat. The colour is a dirty greyish yellow, with traces of violet. The back is covered with tubercles : those in the middle are largest and measure 4 millimetres across ; they decrease in size outwards, and are quite small at the mantle edge. The top of each is lighter, and |