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Show 294 SIR 0 . ELIOT ON NUDIBRANCHS [Nov. 29, larly a large folliculate mass which covers the sides and part of the centre. The largest specimen is 20-5 mm. long and 11 broad across the back. The general construction of the head-parts is as in Phyllo-brcmchus, with the dividing line running down and forming lappets by the mouth, grooved oral tentacles, and grooved bifid rhinophores about 4 mm. long. At the base of these latter can be seen the large black eyes. The genital openings are as in Phyllobranchus, but the intestine terminates dorsally in a cylindrical tube set in front of the pericardium and slightly to the right of the median line. The foot is in two divisions, of which the anterior is the wider, being 17*5 mm. broad by 7'5 in the longitudinal direction of the body, whereas the posterior portion is 12 mm. long by 9'5 at its broadest part. Except for this division, the foot is as in Phyllobranchus prasmus, but the corners of the anterior margin are not much produced. Nearly all the papillae have fallen off, but it appears that they were arranged at the sides of the back, leaving the centre bare. The largest are about 5 mm. high and 3'5 broad. Though they taper towards the base, they have not a distinct stalk. On their margins are 8-10 yellowish spots. The anatomy of this species, like that of Phyll. prasinus, has been elaborately investigated by Bergh (I. c.), but the structure of the hepatic system is obscure. In my specimens most of the papillae are quite transparent, and it seems clear that they contain no hepatic branches, and when they are held out from the body the folliculate mass, which I take to be the liver and which is distinctly visible, is not seen to send any prolongations into their transparent bases. On the other hand, the folliculate mass adheres to the sides of the body-wall in the neighbourhood of the papillae, which it does not do elsewhere, and must be in immediate contact with the openings at their bases. Within the papillae are round bodies which look like minute bubbles, and in some cases it seemed that these bubbles were connected by a system of colourless canals. I have unfortunately no means here (East Africa) of preparing sections for microscopic examination. The radula consists of elongated teeth as figured by Bergh (I. c. pi. xv. figs. 5-11), each bearing 12-17 denticles, but the number of teeth seemed less, and was 14 + 9 in one specimen and 17 + 10 in another. The second figure in these expressions represents the teeth which have fallen down into an irregular heap, and this heap was much smaller than that described and figured by Bergh, possibly in consequence of the youth of the specimens. E l y s i a d .*;. P laco br an ch u s ocellatus Van Hass. = PL. a rgu s B. (Plate XVII. figs. 13 & 13 a.) [B. in S. ft. iii. pp. 147-165, and id. Danish Exp. to Siam, Opisth. pp. 180-181.] Two specimens from Prison Island, Zanzibar Harbour. The larger measured 30 mm. in length, and 15 in breadth when the |
