REPOET ON THE TUNICATA. 
217 
to form a creeping stolon (fig. 9, a and h), and in one or two cases two masses are 
attached by peduncles to the same stolon (fig. 9, 1). One colony from Kerguelen, 10 to 
100 fathoms, consisting of two masses, has no peduncle. Two other colonies from the 
same locality are attached to the long peduncles of Colella pedunculata. 
The colour varies from light grey through various shades of yellowish-grey to brown. 
A warm yellowy-grey, spotted with opaque light yellow is the most usual colour. The 
upper surface is generally uneven and rough, but the peduncle is smooth. The smallest 
colony measures 8 mm. in length and 4 mm. in breadth, the largest (one of the brown 
variety) is 8 cm. in length and 4 ’5 cm. in breadth. 
The Ascidiozooids are conspicuous. Their anterior ends are all placed upon the 
upper, usually broad and rounded, end of the colony (PI. XXIX. fig. 7), and they form 
circular areas from 0'5 to 1 mm. in diameter, raised slightly above the general surface. 
Fig. 9 . — a to 1. Eleven colonies of Amaroucium variabile, to illustrate the extent of individual variation in this species. 
There is usually a common cloacal aperture on the upper end of the colony, and the 
Ascidiozooids are then arranged in several irregular circles around it. In the larger 
colonies there are two or three such apertures on the upper surface, but in some of the 
smaller ones there aj^pear to be no common cloacal cavities present. 
The long narrow bodies of the Ascidiozooids are generally visible on the sides of the 
colony extending downwards towards the peduncle (see fig. 9). The proportions of the 
body of the Ascidiozooid vary considerably in different colonies, and the difference seems 
to be due to the size of the post-abdomen. In some cases, although the anterior region 
of the body is large, the post-abdomen is comparatively short, while in other colonies 
it is of very great length (PI. XXIX. fig. 9, p.ahd.). The Ascidiozooids vary in antero- 
posterior extent from 3 mm. to 10 mm., and in greatest breadth from 0‘5 mm. to 1 mm. 
The thorax is usually about 1 mm. and the abdomen 1 ’5 mm. in length. 
1 The darker specimens, of which there are a considerable number, are mostly larger than the others, and might be 
regarded as forming a distinct variety. They are very, variable in shape. Figures 7 and 8 on Plate XXIX. were drawn 
from one of the brown specimens. 
(ZOOL. CHALL. EXP. PART XXXVIII. 1886.) 
Pp 28 
