REPORT ON THE TUNICATA. 
283 
areas, which are of circular or elliptical form (PL XXXIX. fig. 10), the spicules are 
scarce, and are scattered irregularly, while outside, in the test lying between the 
Ascidiozooids, they are fairly abundant. The six well-marked lobes which surround the 
branchial apertures are strengthened and rendered conspicuous by lines of spicules 
which border their edges (PL XXXIX. fig. 10, hr.). In the deeper layers of the test 
the spicules are abundant. They are scattered irregularly. 
The spicules are not large, and are fairly uniform in size. The}^ are not so large as 
and are less densely packed than in the case of Leptoclinum annectens, which the present 
species resembles somewhat in general appearance. The majority of the spicules are 
regularly stellate in form, and have rather short rays. Here and there a few mammillated 
spherical forms occur, and occasionally deformed or monstrous forms with long irregular 
rays (PI. XXXIX. fig. 11) are found ; these abnormal spicules are, however, very rare. 
The branchial siphon is large. It is lined by a layer of test containing spicules. 
The sphincter is well developed. The branchial sac is small, and is usually crumpled, 
doubtless from contraction in death. The stigmata are long and narrow, and the ciliated 
cells are distinct. 
The endostyle is wide and its course is undulating. The tentacles are short. There 
are eight or ten of them. 
The alimentary canal is small. The stomach is globular and smooth-walled. The 
intestine forms a short wide loop. The testis is large, and has the vas deferens coiled 
spirally around it. 
A few large tailed larvse were found in the colony. They have the body nearly 
circular in outline, with two pigmented sense organs placed on one side, nearer the 
anterior than the posterior end. 
There are some undescribed specimens of Leptoclinum in the British Museum collec- 
tion which were obtained during the cruise of the “Alert,” from (a) Tom Bay, on the 
south-west coast of Chili, depth 0 to 30 fathoms ; and (h) Sandy Point, in the Strait of 
Magellan, which are closely allied to the present species. They differ, however, in 
having the spicules more numerous and of a more spherical shape, the rays being generally 
very short and blunt. 
The “ Lightning ” specimens obtained in the North Atlantic, between Scotland and 
the Faeroe Islands, are all attached to a fragment of Coral (PI. XL. fig. 3). They are 
of small size and of a pure white colour, and agree well in almost all points of structure 
with the Challenger specimens described above. The spicules, however, seem to be 
more closely placed in the superficial layer of the test, and especially over the areas 
occupied by the Ascidiozooids. Most of the spicules are of the same size and shape as 
those in the other specimens of the species (PI. XL. fig. 4), but a few very much larger 
forms of regularly stellate shape, and provided with many rays (PI. XL. fig. 5), occur 
scattered through the test. 
