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 bya deep cleft. The oval 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 bogin at the anterior end of the large peri- 
cardial 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 ave 
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. mebii (see Bergh, /. c. pl. Ixxix. 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 Beolidia, 
and the difference between it and the type is mainly one of size, 
B. mebii 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 cevata may present in AXolids 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. mebii the tentacles are said to be “ iibge- 
plattet fingerformig” ; the cerata begin behind the rhinophores and 
are set in rows: in &, major the tentacles are stout and round ; 
