178 
THE VOYAGE OF H.M.S. CHALLENGEE. 
The Mantle is rather delicate. The muscle bands are all longitudinal in direction ; 
they are narrow and not numerous. 
The Branchial Sac is large and well developed. The transverse vessels are all of the 
same size. The stigmata are large and regular. 
The Dorsal Lamina is represented by a series of large languets. 
The Tentacles are of fair size. There are about a dozen of them, all of much the 
same length. 
The Alimentary Canal is rather large. The stomach has its wall irregularly 
thickened, and the rectum is very wide. 
The Post- Abdomen is long and narrow. Its posterior end is prolonged into several 
ectodermal appendages with slightly dilated ends. 
Locality. — Kerguelen Island; depth, 10 to 60 fathoms. 
This species in general appearance is very similar to Amaroucium variahile, hut 
differs from it in the structure of the stomach-wall and in having eight lobes round the 
branchial aperture. It is also related to Morchellium giardi and to Fragarium 
elegans, Giard. 
There are two colonies in the collection, both from Kerguelen Island, 10 to 60 
fathoms. They are large rounded lumps (PI. XXIV. fig. 16) with no peduncles, and 
having a more regular form than most of the specimens of Amaroucium variahile from, 
the same locality have ; otherwise they resemble that species. The dimensions of the 
larger colony are given above; the smaller one measures 3 cm. in length, 2 '5 cm. in 
greatest breadth, and 1'5 cm. in thickness. Several common cloacal apertures can be 
made out on the surface of each colony. There are no very obvious systems, but the 
Ascidiozooids, though scattered all over the surface, seem to be arranged along the 
borders of meandering lines radiating from the common cloacal apertures (PI. XXIV. 
fig, 16). The anterior ends of the Ascidiozooids show as opaque pale yellow circular 
spots upon the grey test. They give a yellowish tinge to the colony as a whole. 
The Ascidiozooids are fairly large, and the thorax is relatively of larger size than 
is usual in the Polyclinidae. The posterior part of this region is considerably wider than 
any other part of the body. There is no marked constriction where the thorax joins the 
abdomen or where the abdomen joins the post-abdomen. 
Considering its mass, the test is not very solid. The minute test cells present the 
usual variety of shapes ; they are very abundant. The vessels are small and rarely met 
with, as they do not extend far from the posterior ends of the Ascidiozooids. They 
terminate in slight bulbs (PI. XXIV. fig. 17, t.h.). 
The mantle is weak considering the size of the body. The atrial aperture is pro- 
vided with a very long tapering atrial languet. The branchial aperture is provided 
with eight regular and very prominent rounded lobes (PI. XXIV. fig 19, hr.l.). It 
