REPORT ON THE TUNICATA. 
121 
The Ascidiozooids are much elongated antero-posteriorly, and are large. They are 
usually fully 3 mm. in length, and a little over 1 mm. in greatest breadth. They are 
not arranged with regularity. The posterior end is prolonged into a narrow vascular 
appendage. 
The Test is very soft and flexible. The outer layer of the head is smooth but not 
firm. It is very transparent. There are few cells in the homogeneous matrix. 
The Mantle is thin and delicate. The muscle bands are fairly strong but distant. 
The branchial sphincter is large. 
The Branchial Sac is of considerable length. There are at least four rows of long 
stigmata. The transverse vessels are wide. The stio;mata are large and are arranged 
o o o o 
with great regularity. 
The Dorsal Lamina is formed of short languets. 
The Tentacles are very long. There are about twelve, and they seem all of much the 
same size. 
The Alimentary Canal is large, and forms the greater part of the visceral mass. 
Locality. — Station 311, January 11, 1876; lat. 52° 45' 30" S., long. 73° 46' W. ; 
depth, 245 fathoms ; bottom, blue mud ; bottom temperature 46° F. 
Most of the specimens of this species were obtained from a bottle labelled 
“ Compound Ascidians and Gorgonoids from various dredgings, hardened in absolute 
alcohol.” As, however, one small colony was found, along with some specimens of 
Didemnidm, in a bottle from Station 311, on the west coast of Patagonia, it is probable 
that all the specimens of the species were obtained from that locality. 
There are eleven or twelve more or less perfect heads and a large numl)er of 
peduncles, many of them mere fragments. The dimensions given above are those of the 
largest head ; two or three of the smaller ones are only 3 or 4 mm. in greatest length. 
Most of the specimens are more or less torn or injured. The largest colony has three 
heads remaining, and the peduncle branches six times. The colony figured (PI. XV. fig. 14) 
is smaller, but more complete. Usually the peduncle simply bifurcates at each division, 
but in one or two cases (PI. XV. fig. 15) three branches spring from the same point. 
Some of the fragments of peduncle are very long, and give off many branches. 
They are frec^uently incrusted with foreign objects, and in all probability lay on the 
sea-bottom. They are much too weak to support the weight of the head in an upright 
position even in water, and their irregular winding courses suggest that they have been 
recumbent. 
The general shape and appearance of the head is very like that of Colella <pedunculata, 
but the branched peduncle is quite peculiar. The colour of the head varies much. 
In the smaller specimens it is a light grey, while in larger ones it is darker, and in 
the largest it is a very dark grey indeed. The peduncle does not vary so much ^ in 
(ZOOL. CHALL. EXP. PART XXXVIll. — 1885.) Pp 16 
