134 
THE VOYAGE OF H.M.S. OHALLENGEE. 
The Test is soft but fairly tough. It is of a light grey colour and is semi-transparent. 
The matrix contains numbers of small test cells, most of which have rounded for ms . 
Bladder cells are present in abundance in all parts of the test. There are no pigment 
corpuscles. 
Locality. — Eoyal Sound, Kerguelen Island, attached to Macrocystis pyrifera. 
Ten specimens of this small species were obtained from the fronds of Macrocystis at 
Royal Sound, Kerguelen Island. On account of the absence of Ascidiozooids from all 
the colonies it is impossible to refer the species with certainty to its proper position, but 
from the general appearance of the colony there can be little doubt that it is one of the 
Distomidae, more or less closely allied to Colella. 
The colony is always stalked, but the peduncle varies considerably in length. The 
shape of the body proper varies from almost spherical to a long narrow wedge-like form,^ 
but the usual condition appears to be ovate or pyriform (PL XVI. fig. 17). There is 
considerable difference also amongst the specimens in the amount of lateral compression. 
In most of the colonies there are no traces of Ascidiozooids, but in one or two small 
reddish-brown dots are visible placed in vertical rows (PI. XVI. fig. 17), and recalling 
the arrangement of the Ascidiozooids in Colella pedunculata and Colella murrayi. These, 
however, are merely clumps of cells lying in the test, and are the remains of the missing 
Ascidiozooids. In one or two places tailed larvse were found imbedded in the test beside 
these groups of cells. They seemed to be in a fully developed and healthy condition. 
The colonies when collected were probably either in a dying condition and had lost 
their Ascidiozooids, or they were hibernating and the old members of the colony had been 
expelled from the test. In the latter case the tailed larvse which remain may have been 
destined to develop, after a time, into young Ascidiozooids in the old test, without 
passing through a free-swimming condition, and so bring the colony back to active life ; 
or possibly they may have been retained in the test as a protection until a more favourable 
season arrived for being set free before settling down and founding new colonies. 
The test in its minute structure is very like that of several species of Colella 
{e.g., Colella pedunculata, see p. 78 and PI. V. fig. 15). The bladder cells are very 
delicate, but in most places they are abundant. The test cells are small, but very 
numerous. All shapes are found amongst them, but rounded and ovate forms prevail. 
In sections of the colony large spaces are found to occur here and there near the 
periphery. These are evidently the positions which were occupied by the Ascidiozooids. 
Near the centre of the sections, again, there are smaller openings in the test, which 
were probaljly filled formerly by the vascular appendages. In one or two cases the 
remains of the Amscular appendages are to be found, but in most cases, like the Ascidio- 
zooids, they have totally disappeared. 
1 The longest specimen is 3'5 cm. in length. 
