EEPOKT ON THE TUNIC AT A. 
235 
length. The Ascicliozooids are inclined at various angles to the surface of the colony, 
and they are not arranged in regular systems. 
The Test is hard and cartilaginous, and is quite opaque. It is of a dull whitish colour, 
with a slight tinge of grey internally. The matrix of the test is structureless or very 
slightly fibrillated in some places. It contains numerous test cells of various shapes, and 
a few bladder cells. 
The Mantle is moderately strong. The chief muscle bands run longitudinally. 
The Branchial Sac is of small size, and is v’ery narrow. The stigmata are small and 
inconspicuous. 
The Alimentary Canal is relativ’ely small, and forms a narrow loop. 
The Post- Abdomen is large ; it extends for a considerable distance behind the intestinal 
loop. 
Locality.— 162, Aprd 2, 1874; lat. 39° 10' 30" S.., long. 146° 37' 0" W.; 
depth, 38 fathoms ; bottom, sand and shells. 
Two large colonies of this species were obtained in Bass’ Strait from a depth of 
58 to 40 fathoms.^ They are elongated dirty-white masses with rounded ends, and 
having no external marks of importance (PI. XXYI. fig. 11). Both specimens are attached 
by their lower ends to the insides of Lamellibranch shells.^ The area of attaclunent is of 
moderate size, 2 to 3 cm. across. From the base the colony increases somewhat in size as 
it is traced upwards, and it becomes slightly flattened. Above the middle it tapers 
irregularly to the blunted apex. 
The dimensions of the second colony are : — length 5 ’5 cm., breadth near the middle 
4 '5 cm., thickness near the middle 2 cm. In this specimen the thickness decreases 
regularly from the base of attachment to the apex. The lower end is partially 
incrusted with shell fragments, Polyzoa, and other foreign bodies. 
The surface is marked in some places with deep grooves and depressions (PI. XXVI. 
fig. 11), which may be partly the result of irregular contraction, otherwise it is fairly 
smooth, but it is not glistening. The colour is dull white on the projecting parts, 
becoming of a greyish cream-colour in the depressions. No common cloacal apertures 
and no systems of Ascidiozooids are visible on any part of the colony. 
The Ascidiozooids are very narrow, but of considerable length. On cutting open the 
colony their filiform bodies may be seen penetrating the test in all directions. They 
are of an opaque dirty-white colour, sometimes with a yellowish tinge, and are very 
numerous. They probably help in giving the colony its whiteness and opacity, since the 
test around them is slightly grey in hue, and is not so opaque as the surface of the colony. 
The test is very solid and tough, and the outer layer is rather stronger than 
1 That is the depth at the Station, but the parchment label in the bottle is marked 85 fathoms. 
^ A species of Pectunculus {?). 
