ei 
TUNICATA OF THE L.M.B.C. DISTRICT. 951 
Ascidiella virginea, O. F. Muller. ; 
This is probably the commonest species of Ascidian in 
this neighbourhood. It has been found since the former 
report as follows :— 
Several specimens adhering to Hydrallmana falcata 
were dredged off the north coast of Anglesey, in the 
“‘Hyeena”’ expedition of 1886. Half-a-dozen were dredged 
from the centre of the Irish Sea, in the ‘‘ Weathercock”’ 
expedition of 1886. One specimen attached along its left 
side to Zoophytes was collected, about half-tide, at the N.E. 
end of Puffin Island, on December 3rd, 1887. Specimens, 
some of them attached to Hydrallmania falcata by a very 
small area, were dredged off the N.W. side of Puffin Island 
in February, 1888. It was also found at the N.E. end of 
Puffin Island, at extreme low water, in February, 1888. 
Tt is found under stones on the South Spit, Puffin Island, 
at spring tides. Several specimens were dredged off Port 
Erin in the ‘“‘Hyzena”’ cruise of May, 1888; and finally 
one was obtained under a stone at low tide, at Hilbre 
Island, on March 2nd, 1889. 
Many of these specimens, especially those from between 
tide marks, are flat, and attached by the left side, have the 
apertures close together, and bear a strong resemblance 
to Ascidiella scabra, a species which I am inclined to 
regard as the shore variety of A. virginea. Roule has 
pointed out that at Marseilles A. scabra is variable, and 
passes into the varieties of A. aspersa. There is no doubt 
that several of these smaller species of Ascidiella are very 
closely related forms, and are very variable. 
Many of the specimens of A. virginea collected in this 
neighbourhood are very much infested with Modiolaria 
marmorata, aS Many as six large specimens being some- 
times found in one test. I find, however, very few parasitic 
Copepoda in the branchial sac, possibly on account of the 
