EEPORT ON THE TUNICATA. 
145 
vessels of considerable size, with swollen end-bulbs filled with blood-corpuscles. The cells 
in the matrix are very few in number, and of small size. 
The Mantle is strong. The muscle bands are not large, but they are very 
numerous and run in all directions, forming a close but very irregular network. 
The blood-corpuscles are of a dark green colour, and give the mantle a very decided 
tint. 
The Branchial Sac is large, and has a number of stigmata. Internal longitudinal 
bars are present, and they divide the inner surface into meshes. The transverse vessels 
are all exceedingly narrow. The stigmata are large and regularly arranged ; they 
are about equal in width to the fine longitudinal vessels between them. 
The Tentacles are of moderate size, and are all of the same length. They are eight 
in number. 
The Dorsal Lamina is a plain narrow membrane with no ribs nor teeth. 
The Dorsal Tubercle is a small circular aperture placed in a deep triangular peri- 
tubercular area. 
The Alimentary Canal is small, and does not extend far behind the branchial sac. 
The Reproductive Organs are placed alongside the alimentary canaL 
Locality. — Off Bermuda ; shallow’- water. 
This is an interesting and important form on account of the resemblances it shows to 
the Botryllidse on the one hand and to the Distomidse on the other. It is possible that 
when its structure has been more minutely examined in better preserved and more abun- 
dant material it may prove to be more closely allied to the Botryllidse than it is to the 
Distomidse. A single specimen only is present in the collection. It was obtained off 
Bermuda, in shallow water. It consists of about ten heads connected by narrow 
branched peduncles, and closely united to a group of Sponges, Polyzoa, and other foreign 
objects, the whole forming a tree-like mass about 10 cm. in height and 2 ‘5 cm. in 
greatest breadth (PI. XVIII. fig. 7). Unfortunately the specimen is in bad condition 
and is evidently very much shrivelled and distorted, consequently it is impossible to 
get a correct idea of the external appearance. 
The heads vary greatly both in size and shape. The largest is almost 2 cm. in 
length, but is rather narrow ; others are short and broad. The dimensions in the above 
description are taken from a medium sized head. The top is usually wider than the 
base, and is more or less rounded. The sides are not flattened. The lower end of the 
head tapers downwards to the peduncle, which is relatively narrow (PI. XVIII. fig. 7). 
The surface of the head is rendered very uneven by the shrivelling of the test between 
the Ascidiozooids. The colour of the colony is peculiar. The head is a dull sage green 
with a few reddish-brown, or, in some cases, dull orange markings. The peduncle is 
usually a sort of buff or dull yellowish-grey colour. 
(ZOOL. CHALL. EXP. — PART XXXVIII. — 1885.) 
Pp 19 
