469 
of Edinburgh, Session 1879-80. 
muscular process about 4 mm. long projects from the dorsal edge. 
Atrial tube more than half-way down the dorsal edge, and nearly at 
the posterior end of a crested ridge extending backwards from the 
branchial tube. The projecting points of the ridge are attached to 
the inner surface of the test. Right (branchial) side of the body 
long and narrow, left (visceral) very large, occupying all the ventral 
part of the body and even appearing on the right side below the 
branchial sac. 
Branchial sac of moderate size, longish, pointed at the dorsal edge 
of the' lower end ; longitudinally plicated. The internal longitudinal 
bars placed on the ridges. Meshes square, with stout papillae at their 
corners. 
Dorsal lamina ribbed transversely, margin bluntly serrated. 
Tentacles very numerous, crowded, long and slender, varying in 
thickness, but all of much the same length. 
One specimen from Port Jackson, 6 fathoms. 
Ascidia falcigera , n. sp. 
External appearance . — Shape elliptical or nearly round, usually 
depressed. Area of attachment large, extending from the posterior 
end half-way up the left side ; often expanded at the edge of the base 
into a thin spreading margin in which small stones are imbedded. 
Apertures on the upper (right) side, near the anterior end, not far 
apart. Branchial at or close to the ventral border, atrial near the 
centre — the latter is the more prominent though neither projects 
much; lobes very distinct, especially the atrial. Surface smooth 
and soft, slightly wrinkled. Colour from light-grey to pale horn 
tint, darker at the apertures. Length and breadth variable ; as an 
average — length, 5 cm. ; breadth, 4 cm. 
Test thin, except at the base, where it is greatly thickened and 
has always gravel attached to or imbedded in it. Vessels large in 
the base, elsewhere few and of small size. 
Mantle moderately muscular, especially on the tubes and down 
the centre of the right side. Tubes long, atrial much wider than 
branchial, which is bent towards the ventral edge in the middle of 
its length. 
Branchial sac extending to the base of the mantle, not longitudin- 
