149 
lobes and the colouration, the former feature depending 
largely upon the degree of contraction, and the latter, no 
doubt, upon the colour of the seaweed upon which the animal 
lived. 
Dim. — Tlie largest individual that has so far been found 
in South Australia measures 42 millimetres in length, the 
length of the lobes being 16, and height of body 21, making 
a total height of 37 mm. 
Hah. — Dredged in 20 fathoms, 'off Antechamber Bay, 
Kangaroo Island, January, 1903 (Verco) : thrown up on Port 
Willunga beach (Newland). 
Pleurophyllidia cygnea, Bergh. 
Plate X., figs. 1 and 2 : Plate xi., figs. 1-3 ; Plate xii., figs. 1-6. 
P. cygnea, Bergh, Malakol, Blatter xxiii., 1876, p. 9, 
PI. i., figs. 1-7. Id., Semper's Reisen im Arch, der Phil. ii. 
(2), 1892, p. 1063. 
With some confidence we apply Bergh's name to a species 
which we have obtained from St. Vincent Gulf and Sydney 
Harbour respectively. The species appears to be rare and 
not to inhabit the beach zone. Since the original description 
of the animal from the Swan River, Western Australia 
(whence it takes its name), it has not been re-taken by any 
collector. That description was based on an old spirit speci- 
men. We add the following account drawn from a living 
animal : — 
Body elongate, oblong ; sides nearly parallel, terminating 
in a blunt point posteriorly : dorsal surface flat, sloping 
towards the posterior extremity. Mantle (nothaeura) fairly 
ample, slightly waved along the edge, and extending from 
behind the rhinophores : ornamented longitudinally, with a 
series of roughly parallel, black and yellowish, undulating 
ridges, the medial of which extending throughout the whole 
length, the lateral passing out at the sides, bordered with 
yellow. The lobe-like veil is colourless, edged with yellow, 
and with a few yellow spots in its centre. Foot dilated later- 
ally in front, tapering behind : the edge waved and extending 
to beyond the sides of body : it is flat, grooved longitudinally 
along the centre posteriorly, and does not project appreciably 
behind the mantle. Rhinophores longitudinally laminate, 
pink, contractile. Branchis: pink, on the under side of the 
lateral projection of the mantle. Mouth prominent. Geni- 
tal orifice and anus prominent on the right side, the latter 
19 mm. behind the former. The entire under-surface a uni- 
form light crimson. 
Radula pale yellow. Lateral spines numerous, about 70, 
of equal size, except the most central, which are smaller than 
