Plate 104. 



1-5. Periaster tenuis A, Ag. 



1. Specimen 58 mm. in length, seen from the actinal side, partly denuded ; Station 3398. 



2. The same as fig. 1, seen from the abactinal side, partly denuded. 



3. The same, seen in profile facing the right posterior interambulacrum. 



4. Another specimen, 67 mm. in length, seen from the actinal side; Station 3399. 



5. The same as fig. 4, seen from the actinal side. 



