104 
THE VOYAGE OE H.M.S. CHALLENGER. 
The Reproductive Organs are not very conspicuous. A large incubatory pouch 
projects from the dorsal edge of the peribranchial cavity. 
Locality. — Port William, Falkland Islands; January 27, 1876; depth 5 to 10 fathoms. 
Four large colonies and one very young one are included in this species. They were 
obtained at Port William, on the eastern coast of the Falkland Islands, from a depth of 
5 to 10 fathoms. 
The above description and measurements were taken from three of the larger 
specimens. The fourth differs slightly, but is not sufficiently distinct to be placed in a 
separate species. The head is larger and flatter, so as to be somewhat discoid, but its 
lower end is broader than the upper, and has a truncated appearance. The exact 
dimensions are as follows : — Length of the head 13 mm., breadth 16 mm., average 
thickness 4 mm. Length of the stalk 18 mm., thickness at the upper end 3 '5 mm., at 
the lower end 1 mm. The colour in this specimen is rather paler than in the other 
three, the head being yellow with no tinge of brown, and the peduncle a clear light 
grey, except the point of attachment, which is slightly brownish. 
The very young colony consists of a peduncle about 8 mm. long, and a rounded 
head scarcely 2 mm. in length and about 1‘5 mm. in breadth. 
In all the specimens the form of the colony is club-shaped (PI. XIV. fig. 7), and the 
peduncle tapers from the base of the head to the point of attachment. There is a 
certain amount of variability in regard to the lateral compression and also in the position 
of the broadest part of the colony. The peduncle is always of a lighter colour than the 
head, and is much greyer than the peduncle of Colella pedunculata. 
The Ascidiozooids are very distinct ; they are large and are closely placed. They 
appear as opaque yellow spots which may be as much as 2 mm. in greatest diameter 
(PI. XIV. fig. 7). This is not the anterior end alone ; on account of the irregularity 
in the position of the Ascidiozooids, a considerable part of the body in many cases shows 
through. There seems to be no regular arrangement of the Ascidiozooids in lines or 
groups, and they are not imbedded in the test at right angles to the surface of the 
colony, but lie inclined at various angles. In transverse sections they are seen to occupy 
nearly the whole of the interior of the head, there being no central free region 
of the test. The size of the Ascidiozooids varies greatly. The broadest part is 
generally where the stomach is placed. The vascular appendage is long and nar- 
row. In the younger Ascidiozooids (see PI. XIV. fig. 12) it is about twice the 
length of the body. Its lower end is rounded and usually a little swollen, forming a 
knob. 
The cells in the test are extremely numerous and of fairly large size (PI. XIV. fig. 9, t.c.). 
Their processes are in some cases very long and branched. The mantle has its muscle 
bands mainly transverse in direction. 
