REPOKT ON THE TUNJOATA. 
347 
The Ascidiozooids are not large, and they are not very numerous. As a rule there is 
one Ascidiozooid in each of the rounded masses of the colony, but in some cases several 
Ascidiozooids are placed together in one mass ; the apertures are in most cases placed 
upon slight papillae projecting from one end of the Ascidiozooid ; they are both four- 
lobed. The body of the Ascidiozooid is not elongated, and is not divided into regions. 
The Test is thin, and tough and leathery, but not stiff. It is quite opaque. The 
matrix is minutely fibrillated in places. There are a few small rounded test cells, but no 
bladder cells are present. Vessels are found ramifying through the test. They are 
rather narrow, and do not branch much ; the terminal twigs end in small rounded knobs. 
The stolons are penetrated by vessels. 
The Mantle is strong, and has a well-developed musculature. The branchial and 
atrial sphincters are powerful. 
The Branchial Sac is large and well-developed. Eudimentary folds are present, and 
the internal longitudinal bars are strong and conspicuous. The transverse vessels are 
moderately wide, and have slight horizontal membranes. The meshes are slightly 
elongated transversely, and contain each six or seven stigmata. They are divided by 
delicate transverse vessels which do not interrupt the long narrow stigmata. 
The Dorsal Lamina, is a plain narrow membrane with no ribs and no marginal 
teeth. 
The Tentacles are rather short and stout. There are about twenty-four of them, and 
they are of two sizes placed alternately. 
The Dorsal Tubercle is very large. It is elongated antero-j^osteriorly, and extends 
from the base of the tentacles to the dorsal lamina. The aperture is a long narrow slit. 
The Alimentary Canal lies alongside the posterior part of the branchial sac. It is 
not large. The stomach has no well-marked folds. 
The Reproductive Organs are in the form of polycarps, which are attached to the 
mantle. They are of small size, and are unisexual. 
Locality. — Station 149d, January 20, 1874; Koyal Sound, Kerguelen Island; lat. 
49° 28' S., long. 70° 13' E. ; depth, 28 fathoms; bottom, volcanic mud. 
Station 149e, January 21, 1874; Greenland Harbour, Kerguelen; lat. 49° 37' S., 
long. 70° 16' E. ; depth, 30 fathoms; bottom, volcanic mud. 
Two large and several small colonies of this interesting species were obtained with 
the dredge from a depth of 30 fathoms in Koyal Sound, Kerguelen Island. 
Many of the Ascidiozooids are almost completely independent of one another 
(PI. XLVI. fig. 2), being merely united by basal creeping stolons as in the case of the 
Clavelinidse, but in other parts of the colony two or more Ascidiozooids may be found 
imbedded in the same mass of test (PI. XLVI. fig. 3) as in the case of other Compound 
Ascidians. This species is therefore on the border line between the two groups, and 
