56 
THE YOYAGE OF H.M.S. CHALLENGER. 
is composed of testes only, while in young buds a series of ova, one or two of which 
appear mature, occupy the same region. This species, therefore, like some others, is 
protogynous (see p. 45), 
Sarcobotrylloides, von Drasche. 
Sarcohotrylloides, von Drasche, Die Synascidien der Bucht von Eovigno, Wien, 1883, p. 14 
(as a subgenus). 
Colony thick and fleshy, often lobed. 
Systems elliptical, or elongated, forming branched and sometimes anastomosing 
lines. 
Ascidiozooids cylindrical, with the apertures placed near one another on the 
anterior end. 
Test gelatinous, rather solid and greatly thickened, many vessels present. 
Branchial Sac large and well developed. 
Tentacles eight to sixteen in number. 
Alimentary Canal placed alongside the posterior part of the branchial sac. 
Reproductive Organs placed on both sides of the body near the posterior end. 
This genus was instituted by von Drasche in 1883 as a subgenus of Botrylloides, for 
the reception of a species bearing the same relation to other species of Botrylloides that 
Polycyclus does to Botryllus. As I have stated before (p. 38), I consider Sarcobotrylloides 
sufficiently well characterised to be raised to generic rank, and I am glad to be able to 
add a second species which is quite as distinct as Sarcobotrylloides superbum, von 
Drasche, from members of the allied genus Botrylloides. 
Colonies of Sarcobotrylloides form thick solid masses, which may be irregularly lobed 
on the outside, or produced into processes. 
The systems are precisely like those of the genus Botrylloides. The Ascidiozooids 
occupy only the outer parts of the colony, the centre being formed by a solid mass of test, 
penetrated by vessels which may have dilatations in which buds are produced. In shape 
and anatomy the Ascidiozooid is almost exactly like that of Botrylloides. 
The new species described below was obtained during the cruise of H.M.S. 
“ Porcupine ” in 1869, half way between the Butt of Lewis and the Faeroe Isles, at a depth 
of 363 fathoms, a very considerable depth for one of the Botryllidae to inhabit. It differs 
from von Drasche’s species {Sarcobotrylloides superbum), the only other known species of 
the genus, in many particulars. The colour of the colony as a whole, and of the several 
parts, is quite different in the two species ; the test, for example, is opaque white in 
Sarcobotrylloides superbum, and of a pale pink or light purple colour in Sarcobotrylloides 
wy villa. The common cloacal apertures are stated by von Drasche to be few but large, 
with projecting margins. In the “ Porcupine ” specimen none are visible, still this is 
