124 
THE VOYAGE OF H.M.S. CHALLENGEE. 
The Dorsal Tubercle is a small circular opening at the base of the most anterior 
lano;uet. 
O 
The Alimentary Canal is large and conspicuous. 
The Reproductive Organs lie alongside the intestine. The adult Ascidiozooids are 
hermaphrodite. 
Locality. — Kerguelen Island; depth, 10 to 60 fathoms. 
One very large colony and several smaller specimens of this species were collected 
at Kerguelen Island from depths of 10 to 60 fathoms. 
The larger colony (see PI. XVI. fig. 8) consists of about thirty irregularly club- 
shaped masses all joined together by their lower ends. Each of these may be called a 
system.^ The smaller systems are each merely a small knob, the upper rounded free end 
of which contains a few young Ascidiozooids, while the lower part, consisting of a mass of 
test penetrated by the vascular appendages, forms a short stalk. In the larger systems 
the shape is much more irregular. The head expands laterally so as to become more 
flattened on the upper surface, which, however, is always a little convex (PI. XVI. fig. 8). 
This upper surface is more or less circular in outline, and has a well-defined edge from 
which it rapidly narrows downwards to the top of the stalk. The length of the head 
(from the top of the stalk to the highest point of the convex upper surface) is usually 
considerably less than the average diameter of its upper surface. In a head the length 
of which is 8 mm., the average diameter is about 12 mm. 
The stalk, even in the largest systems, remains narrow at its lower fixed end, but 
thickens greatly and in some cases very irregularly as it is traced upwards to the head 
(PL XVI. fig. 8). There is a great deal of variability both in length and thickness of 
stalk, but on an average the top is about three or four times as thick as the base. 
The general shape and appearance of the small systems is very like that of many 
specimens of Amaroucium proliferum, while the larger systems approach more the forms 
seen in the genus Distaplia. 
The colour of the colony approaches yellow rather than grey. The stalk is yellowish- 
grey and nearly quite opaque. Here and there a more yellow and more opaque line 
may be seen running longitudinally for a short distance. This is caused by a vascular 
appendage lying close to the surface. 
The test of the head is distinctly greyer and more transparent, allowing the yellow 
opaque bodies of the Ascidiozooids to show through with considerable clearness. In one 
or two systems openings resembling common cloacal apertures were found about the 
middle of the upper surface of the head, but in most cases, on account of the extreme 
delicacy of the superficial layer of test, it is impossible to make them out. 
’ The relation of these masses to the regular systems, of Botryllus for example, is difficult to determine from spirit 
specimens ; possibly some of them have more tlian one common cloacal aperture, and are therefore equivalent to several 
true systems. 
