Van Name. — Simple Ascldians. 
PLATE 59. 
Fig. 
89. 
Fig. 
90. 
Fig. 
91. 
Fig. 
92. 
Fig. 
93. 
Fig. 
94. 
Fig. 
95. 
Tethyum ruslicum (Linnaeus). 
Tethyum rusticum (Linnaeus). 
Tethyum rusticum (Linnaeus). 
Tethyum atlanticum, sp. nov. 
side next to mantle. X 6. 
Tethyum atlanticum, sp. nov. 
Tethyum partitum (Stimpson). 
Tethyum partitum (Stinipson). 
Part of branchial sac. X 10. 
Part of gonad. X 9. 
Dorsal tubercle. X 11. 
One of the gonads as seen from 
Dorsal tubercle. X 9. 
Dorsal tubercle. X 9. 
One of the right gonads as seen 
from side next to mantle. X 8. 
