EEPORT ON THE TUNICATA. 
129 
Localities. — (a) Tangier Bay, on the coast of Morocco ; depth, 35 fathoms. One large 
colony with two heads, obtained during the cruise of H.M.S. “Porcupine” in 1870. 
(b) Station 212 ; lat. 6° 54' N., long. 122° 18' E.; depth, 10 to 20 fathoms; January 30, 
1875 ; bottom sand. 
The species of this genus appear to he very yariable in shape and pigmentation, and 
it is a difficult matter to determine how far external characters are of value as diagnostic 
features. The above specific description is taken from the largest of the Challenger 
specimens obtained at the Philippine Islands, and the other smaller specimens agree 
with it closely. The peduncles spring from an irregular stolon-like base of a light grey 
colour, considerably incrusted with sand-grains and shell fragments (PI. XVIII. fig. 1). 
The peduncle is always stout, and its length is about three times its average thickness. 
It widens somewhat as it is traced upwards from the base, and passes gradually into the 
head at the top. The rosy tint is most marked at the upper end of the peduncle ; lower 
down the colour is greyish. The head is dome-shaped in the largest specimen (PI. XVIII. 
fig. 1), and more rounded at the top in the others. There is a common cloacal aperture 
near the centre of the upper end, and from this lines of Ascidiozooids radiate outwards and 
downwards to the equatorial region. Consequently each head contains one system only. 
There are no Ascidiozooids below the equatorial region, the widest part of the head. 
The Ascidiozooids form about twenty rows, and there are about five in each row ; the 
branchial apertures are very distinct. The surface of the head is smooth. Its colour 
is rose-red below the equatorial part, passing into dark shades of purple and violet 
above, and finally becoming almost black at the top around the common cloacal aperture. 
The margins of that aperture and also of the branchial openings of the Ascidiozooids 
are marked with a line of opacpie wdiite pigment. 
The “ Porcupine ” specimen from Tangier Bay (see PI. XVIII. fig. 2) is larger than 
any of the Challenger specimens, and consists of two heads supported by stout branches 
of a single peduncle. The larger head is 11 mm. in length and 15 mm. in greatest 
breadth. The branch of the peduncle which bears it is 12 mm. in length and 10 mm. in 
greatest breadth, while the common basal part of the peduncle is about 20 mm. in length 
and G mm. in average breadth. The general character of this colony agrees fairly with 
that of the Challenger specimens, the only peculiarity being that the peduncle is here 
branched. Possibly the common basal part of the peduncle ought to be regarded as 
corresponding to the stolon in the other specimens. In colour the “ Porcupine ” specimen 
agrees well with the descri])tion given above. The head is not quite so dark, and shows 
a good deal of red pigment even above the equatorial line. The upper end has a con- 
siderable amount of violet and black pigment. There can be no doubt, I think, that 
notwithstanding the branched peduncle, the larger size, and the somewhat lighter colour, 
the colony from Tangier Bay must be referred to the same species as those from the 
Philippine Islands. It may, however, be regarded as a variety. 
(ZOOL. CHALL. EXP. PART XXXVIII. — 18S5.) 
Pp 17 
