REPORT ON THE TUHICATA. 
213 
from Kerguelen, 10 to 60 fathoms, consists of four ovate masses united irregularly by 
thick peduncles. This colony is much larger than any of the others. The unevenness of 
the surface in some of the specimens is, I believe, the result of unequal contraction at 
death. 
The upper end of the colony is always rounded, and the point of greatest breadth is 
usually not far from this end (PL XXYI. fig. 8). The dimensions given above are taken 
from one of the medium sized specimens. The largest colony in the collection measures 
about 9 cm. in length and 4 cm. in greatest breadth. The smallest specimen is 1 1 mm. 
m length and 6 mm. in breadth. 
The Ascidiozooids are large and not numerous (PI. XXVI. fig. 8) ; they are not 
arranged with any regularity. They lie more or less vertically in the test, and their 
anterior ends nearly all open upon the convex upper end of the colony. In the specimens 
from Eoyal Sound, Kerguelen, and the large colony from Kerguelen, 10 to 60 fathoms, 
the Ascidiozooids are particularly conspicuous, and form large opaque yellow marks upon 
the exterior of the colony. 
The test is firm to the touch but tears readily. The outer layer is rather harder and 
tougher than the interior. It is rather opaque, and only allows the Ascidiozooids to 
show through w'hen they are close to the surface. 
There are no bladder cells and apparently no vessels present (PI. XXVI. fig. 9). 
The small test cells are of various sizes and shapes, and many of them are darkly 
pigmented. These pigment cells are rather more numerous in the outer layer of the 
test and immediately around the bodies of the Ascidiozooids than elsewhere. In some 
places they lie closely crowded together so as to form groups in which some of the cells 
have become more or less polygonal from mutual pressure (PL XXVI. fig. 9, t.c'.). 
The mantle is strongly muscular, and both longitudinal and transverse bands are 
present, although the former are the largest and most numerous. In some places the 
muscle bands are very wide and are found to brfinch and anastomose freely. The 
ectoderm can be stripped off as a distinct membrane from the surface of the mantle. 
It is formed of rather large polygonal cells. 
The branchial sac is in a very rudimentary condition. As the stigmata are few in 
number and are reduced to small rounded apertures rather irregularly placed, it is 
impossible to distinguish the usual systems of vessels. 
The alimentary canal is short and wide, and of an opaque yellow colour. The 
reproductive organs are placed close behind the intestinal loop, consequently the post- 
abdomen is very short. Young and mature ova of various sizes were found in the 
Ascidiozooids. 
The remaining organs of the body were not worked out in detail on account of the 
unfavourable condition of the specimens for examination. The tissues are all exceedingly 
opaque, and the Ascidiozooids, especially in their anterior parts, are much contracted. 
