PLATE XIII. 



Figs. 1 — 6. Stichaster albulus. 1, 3, 4 and 6 represent specimens with 

 abnormal reproduction of arms; 2 and 5 represent full- 



grown specimens, ^/i. 



7 — 8. Ophiopleura borealis, abnormal specimen; 7 ventral, 8 dor- 

 sal aspect. Vi. 



