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Show 1903.] FROM EAST AFRICA AND ZANZIBAR. 253 One specimen from Chuaka, E. coast of Zanzibar, under a stone between tides. The living animal was about 4 centimetres long. The body and appendages were of a uniform greyish white, with spots of a dull opaque white. The whole animal closely resembled a kind of detachable sea-anemone which is very common at Chuaka, and appears to be sometimes almost free-swimming. The alcoholic specimen is 3 centim. long and 1 centim. broad at the widest part, including the cerata. The foot is moderately broad, and has fairly long tentacular expansions in front; but its most remarkable character is the size and distinctness of the anterior groove, which measures 2 millim. across. The upper lip is separated into two parts by a deep cleft. The oral tentacles are large and very thick. The rhinophores are shorter and studded with minute knobs, which, in the preserved specimen at any rate, appear not to be set in rings. The cerata are much flattened and almost leaf-like, and the hepatic diverticula within them are ramified. They begin at the anterior end of the large pericardial prominence, and are arranged in about 17 groups on each side, each containing about 10 cerata. There are very distinct gaps between the anterior groups, and a broad bare space runs down the middle of the back, but towards the end of the body the cerata are huddled together and continue until the extreme tip, there being no tail. The outermost cerata of all the rows are smaller, and the inner considerably larger, but at the base of the innermost are frequently quite small, some hardly larger than tubercles. The genital orifice is below the first group of cerata, and the lateral vent behind the second. The specimen was only partially dissected. The jaws are very large, colourless and transparent, with a perfectly smooth edge. The radula consists of 32 pectinate teeth, very similar to those of B. mcebii (see Bergh, I. c. pi. lxxix. fig. 16), with striations under each denticle. They are, however, very much broader, the widest measuring 2 millim., and the denticles are more irregular in shape, being probably worn by use. There are about 150 of them on the broader teeth. The three or four central denticles are generally, but not always, smaller than the others. This specimen is clearly referable to Bergh's genus Bceoliclia, and the difference between it and the type is mainly one of size, B. moebii being only 8 millim. long. The similarity of habitat makes one think that this may be merely a full-grown individual of the same species; and we know so little of the variations which the radula and arrangement of cerata may present in zEolids at the different periods of their growth, that I am not prepared to reject this hypothesis. Still, the single specimen examined by Bergh appears to have been sexually mature, and this being so the two animals each present peculiarities amounting to specific differences:-(1) In B. mcebii the tentacles are said to be " abge-plattet fingerformig" ; the cerata begin behind the rhinophores and are set in rows: in B. major the tentacles are stout and round |
