198 CATALOGUE OF THE MOLLUSCA 
conical, but not much produced, and when retracted, so completely 
on a level with the surface, as to be imperceptible. Outer tunic 
soft, transparent, and colourless, shewing the viscera and branchise 
very distinctly within : the intestine is seen forming a yellowish 
brown coil; a bright reddish spot indicates the stomach ; and 
the ovaries form an opake white central mass oneachside. The 
inner tunic is very thin, soft, and colourless. The branchial sac 
has about twelve deep and broad longitudinal folds, which are di- 
vided by transverse bars into small cells, opening externally to- 
wards the tunic, and, when viewed through its transparent walls, 
appearing like rows of chains or festoons ; the intermediate re- 
ticulations are small. The aperture to the branchial sac is 
fringed internally with a circle of beautifully branched yellow 
tentacles. Diameter about three-quarters of an inch. 
Molgula tubulosa, Forb. and Hanl. i. 36, t. C, fi 5. 
Brought up plentifully on the fishermen’s lines at Cullercoats. 
It is always encrusted with sand, but not so deeply as Cynthia 
ampulla, and there is often a transparent spot, free of sand, at 
one side, which gives to these little balls somewhat the appear- 
ance of detached eyes. They are so abundant in some parts of 
the fishing grounds that they are caught by the hooks in con- 
siderable numbers, to the great annoyance of the fishermen. 
We cannot find any description agreeing with this species. 
It appears to us to come nearest to the Ascidia punum of Miil- 
ler, but our friend, Professor H. Forbes, who has seen our draw- 
ings of it, refers it to Ascidia tubularis of the “Zoologia Da- 
nica.” That species, however, is described to be greenish, 
opake, and verrucose,—while ours is hyaline, transparent, and 
smooth. It is also stated to be attached by its base to the roots 
of Fuci: ours is always free. We have thought it best, there- 
fore, to consider it as undescribed, and to give such details of it 
as may serve for its recognition in future. 
M. crrriwa, Ald. and Hance. 
Body convex, ovate, attached to stones in a diagonal direction 
by a broad base; nearly smooth, yellowish and semi-transparent, 
with a deep yellow or orange-coloured patch at the lower end 
from the viscera appearing through. Branchial aperture sub- 
