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Show 1904.] FROM EAST AFRICA AND ZANZIBAR. 101 My specimens seem to be on the whole smaller than those of Bergh and to have fewer cerata. B ornella d ig it a t a Adams. (Plate IY. fig. 5 a.) [A. & H., Notes on a Coll. of Nud. made in India, p. 140, pi. xxxiii. figs. 8, 9 ; Bergh, S. R. vii. p. 301 ; id. Danish Exp. to Siam, Opisthobranchiata, p. 199.] Several specimens from Zanzibar Harbour (Bawi and Prison Island). The living animals were white, with a granulated surface. On the back was a reticulate pattern of deep orange. The cerata were tipped with opaque white, below which was a band of bright orange. The transparency of the body-walls varied in different specimens. In some the liver and its ramifications were clearly visible. The following description, when not otherwise stated, applies to the largest alcoholic specimen; the others are much like it, but the smaller ones are only half the size. Length 30 millimetres, breadth 4, height 8'5 ; much compressed laterally. On each side of the mouth is a large branched process with about fifteen subdivisions ; of these the four or five uppermost are larger and digitate ; the remainder are round and tubercular. The back bears a pair of rhinophores with appendages, and, as a rule, four pairs of cerata behind them. The largest specimens have a fifth pair of small cerata, which in one case are fused together into a single process. The rhinophore-sheaths are raised ; they bear in front three small digitate processes, and behind one long tapering' pi •ocess which rises 5-5 111111. above the rhinophores. The first pair of cerata are divided into two large and two small fingers; the right-hand member of the second pair into two approximately equal fingers, and the left into two large and one small; the third into one large and one small finger; the fourth are simple; the fifth are merely small warts. In the smaller specimens the first pair of cerata are trifid only, and in the smallest bifid, with indications of an incipient third digit. It appeal's probable that the number of digits increases with size and age. The first pair of cerata bear three branchiae, the second, third and fourth two, the fifth none. The branchiae are all on the inner side of the cerata and set close together. The labial armature consists of small overlapping scales, arranged in fairly regular rows. The edge of the jaws is quite smooth. The radula consists of 34 rows. The median tooth has a long central cusp, with from 8 to 10 denticulations or ridges at the base. In most rows there are 9 laterals, increasing in size from the innermost outwards, but in some the number rises to 13 and 15. The walls of the second stomach are raised into folds on which are set large brown thorns, with rather blunt tips. The ramification of the liver appears to be very irregular and to vary in different specimens. In the largest the arrangement is as follows:- A single branch runs up into the tall tapering process behind each |