220 
THE VOYAGE OF H.M.S. CHALLENGER. 
77? e Branchial Sac is large, and has numerous rows of stigmata placed with great 
regularity. The stigmata are rather short and rounded. 
The Dorsal Lamina is represented by a series of languets. 
The Alimentary Canal is of moderate length. The stomach is short and wide, and 
has a few longitudinal folds. 
77?e Post- Abdomen is long and tapers towards the free end. It contains both male 
and female reproductive organs at the same time. 
Locality. — Kerguelen Island; depth, 10 to 60 fathoms. 
Two specimens in the collection made at Kerguelen Island have been referred to this 
species, but they differ somewhat in their characters. The description given above is 
taken from the larger colony (PI. XXIX. fig. 1). The other dilTers from it in having 
almost no peduncle, the globular mass in which the Ascidiozooids are placed being 
attached by its lower end to a projection composed partly of a prolongation of the test, 
but mainly of incrusting Sponges and other foreign objects (PI. XXIX. fig. 2). The test 
of this colony is exceedingly soft and flexible, and the Ascidiozoods are more numerous 
than in the larger specimen. The length (exclusive of the prolongation at the base) is 
1'6 cm., the breadth is 1‘8 cm., and the thickness is 1’3 cm. 
In both cases the Ascidiozooids are situated near the base of the globular part of the 
colony, having apparently been retracted from the upper surface (PI. XXIX. figs. 1, 2). 
In both specimens the Ascidiozooids are clearly visible as pale yellow opaque spots upon 
the clear yeUowish-grey test. In the smaller colony (PI. XXIX. fig. 2) they are rather 
shorter and broader than the dimensions given in the above description. The arrange- 
ment of the Ascidiozooids is the same in both specimens. They are placed vertically in 
the test, but it is rather difficult to make out the exact shape of the systems. These 
are not very large, and they are in an intermediate condition between the form found 
in the genus Botryllus and that characteristic of Botrylloides. The common cloacal 
apertures are of small size and are circular in outline. 
The test cells are very varied in form, and nearly always have long delicate 
processes ; stellate and branched forms are very common. In addition to the longi- 
tudinal muscle bands, the mantle is provided with numerous very delicate fibres which 
run transversely and obliquely over the thoracic region of the body. The longitudinal 
bands are numerous and very regularly placed on the post-abdomen. The atrial 
aperture is provided with a narrow tapering atrial languet which varies considerably in 
size in different Ascidiozooids. It is often much longer than is shown in the figure 
(PI. XXIX. fig. 4, at.l.), and in one case was found to be bifurcated, each half tapering to a 
pointed apex. 
The l?ranc]iial sac is generally about 1‘5 mm. to 2 mm. in length and 1 mm. in 
breadth. The numerous transverse vessels are all of the same size, and are prolonged 
