Van Name. — Simple Ascldians. 
PLATE 56. 
Fig. 68. Pyura ovifera (Linnaeus). One of the smaller (third order) branches 
of a large tentacle. The numerals show the fourth, fifth, and 
sixth order branches which it bears. X 37. 
Pyura oi'ifera (Linnaeus). Dorsal tubercle. X 7. 
Pyura ovifera (Linnaeus). Part of external surface of a rather 
small individual showing spines. X 11. 
Pyura aurantium (Pallas). Oral tentacles. X 9. 
Pyura aurantium (Pallas) . Part of external surface of body. X 10. 
Pyura aurantium (Pallas). Dorsal tubercle. X 7. 
Pyura aurantium (Pallas). Gonad. X 21. 
Microcosmus nacreus, sp. nov. Dorsal tubercle. X 8. 
Microcosmus nacreus, sp. nov. Oral tentacle. X 9. 
Microcosmus nacreus, sp. nov. Left gonad and part of intestinal 
loop. X 2. 
Culeolus suhmi Herdman. Dorsal tubercle. X 8. 
Culeolus suhmi Herdman. Processes from border of branchial 
aperture. X 9. 
Culeolus suhmi }ierdmsin. Part of external surface of body. X 7. 
Culeolus suhmi Herdman. Oral tentacles. X 9. 
Fig. 
69. 
Fig. 
70. 
Fig. 
71, 
Fig. 
72. 
Fig. 
73, 
Fig. 
74, 
Fig. 
75. 
Fig. 
76, 
Fig. 
77, 
Fig. 
78. 
Fig. 
79. 
Fig. 
80, 
Fig. 
81, 
