Van Name. — Simple Ascidians. 
PLATE 62. 
Fig. 104. Tethyum plicatum (Lesueur). Part of branchial sac. X 13 
Fig. 105. Tethyum plicatum (Lesueur). Dorsal tubercle. X 13. 
Fig. 106. Tethyum molle (Stimpson). Part of branchial sac. X 25. 
