252 
THE VOYAGE OF H.M.S. CHALLENGEE. 
collection there is a large colony (about 3 feet in length^) labelled “ Antarctic ” which I 
believe belongs to the same species. 
The British Museum specimen appears to be in a semi-decayed condition, the surface 
is irregular, and the Ascidiozooids are many of them partially ejected from the test. 
Both ends of the colony are frayed out, and one of them is in a matted condition and was 
probably the point of attachment. From the presence of sand grains adhering to the 
surface all along the specimen it is very probable that the colony was unable to grow 
erect, and simply lay along the sea-bottom. 
The two specimens in the Challenger collection are even in worse condition for 
anatomical purposes. The whole of the surface is evidently decayed and rotten. The 
bodies of the Ascidiozooids are exposed, and are more or less .torn and displaced, while 
even those which are in their natural positions are so decomposed that it is impossible 
to make out anjdhing definite as to their structure. One colony, from which the above 
description and measurements were taken, is apparently complete (PI. XXVIII. fig. 14, 
represents this colony on a reduced scale), the other is probably only a fragment. 
The complete colony consists of (l) a basal portion about 2 cm. in length, and 
frayed out into rootlets to which sand and stones are attached, (2) a region im- 
mediately above this, and measuring 3 cm. in length, where the test is solid but 
there are no Ascidiozooids, and (3) the rest of the colony, about 43 cm. in length, 
where there are Ascidiozooids scattered irregularly all over the surface (see PL XXVIII. 
fig. 14). The second specimen measures 25 cm. in its extreme length and 3 cm. 
in breadth. It is widest about half-way up, and tapers to about 1 cm. in breadth 
at the top. There is no base of attachment, and probably a good deal of the 
lower part of the colony is absent. Both specimens have sand grains adhering to the test 
at various parts of the surface (PI. XXVIII. fig. 15) ; they were probably recumbent in 
position. 
The Ascidiozooids show as small rounded yellow bodies about 2 mm. in diameter, 
imbedded in or partially projecting from the superficial layer of the test (PI. XXVIII. 
fig. 15). There appear to be no portions of their bodies in the deeper parts of the colony, 
the centre being merely a mass of spongy test. The bodies of the Ascidiozooids are quite 
opaque, and they show no division into regions. Considering the great size of the colony, 
they are small. On some parts of the surface they are absent for considerable distances 
(3 or 4 cm.) (PI. XXVIII. figs. 14, 15), but I believe that this is not the natural condition, 
but simply the result of the decomposition. 
The test is of gelatinous consistence throughout, and, considering its light colour, is 
remarkably opaque. The test cells are large and very numerous. A microscopic 
examination of the Ascidiozooids in the Challenger specimens gives no results. 
The mantle can be made out in a semi-decayed condition, but inside that the branchial 
^ This is the largest Coinpouad Ascidian I have met with. 
