460 
Proceedings of the Royal Society 
ASCIDIADAL 
I 
Branchial aperture 
eight-lobed. 
Viscera on right side. 
Stigmata curved. 
Corella. 
Viscera on left side. 
Stigmata straight. 
Branchial aper- 
ture more than 
eight-lobed. 
Abyssascidia. 
A. wy villii. 
C. japonica. 
Viscera extending 
beyond branchial 
sac posteriorly. 
Dorsal lamina 
in the form of 
languets. 
Ciona. 
Viscera of same length 
as branchial sac. 
Dorsal lamina in the 
form of a membrane. 
Ascidia. 
C. flemingi. Test normal. 
Tentacles crowded, 
not long and short 
Tentacles long and 
short alternately. 
Test very thick and 
solid. 
Pachychlcena 
(sub-gen.). 
alternately. 
1 
Test dark-col- 
oured. Ten- 
tacles long and 
short alter- 
nately. Dor- 
sal lamina pec- 
tinated. 
Branchial sac plicated. 
Mantle forming a 
crest between tubes. 
| 
Branchial sac not 
plicated. No 
crest on mantle. 
| 
A . pyriformis. 
A. falcigera. 
| 
Tentacles, Tentacles, 60 
30-35. long and 60 
very short. 
P. obesa. 
P. oblonga. 
| _ | 
Test light-col- 
oured. Ten- 
tacles not long 
and short 
alternately. 
Dorsal lamina 
not pectinated. 
P. gigantea. 
Branchial sac not plicated. 
A. tenera. 
Branchial sac plicated. 
Small intermediate papillae ; 
olfactory tubercle normal. 
No intermediate papillae ; 
olfactory tubercle serpentiform. 
A. translucida. 
Test light-coloured. Test indigo-coloured. 
! I 
i | A. nigra. 
Tentacles 60. Tentacles 30. 
I I , 
A. meridionalia. A. mentula. 
