Plate 77 

 All figures from living specimens of Pycnopodia helianthoides, Monterey Bay, Calif. 



Fig. 1. Oral angle. Showing the mouth plates al top, and five pairs of adambulacral plates of the 

 adoral carina, with their clusters i>f straight pedicellariae. The peduncles are in a 

 state of contraction; X7. 



2. Three superomarginal spines, and below a small portion of the abactinal surface at middle 



of ray, showing the large compound papulae (P) with their attendant dwarf and giant 

 straight pedicellariae. The sheaths of the three marginal spines, carrying crossed 

 pedicellariae are shown expanded and contracted. The abactinal sheath of crossed 

 pedicellariae in the midst of the four groups of papulae is without a central spine. 

 Enlarged about eight time-. 



3. Actinal surface of a ray showing the inferomarginal and adambulacral spines and the mobile 



clusters of pedicellariae in various postures. Note the differentiated ciliated channels 

 t ra \ ersing t he skin, X S. 



4. A tube-foot enlarged, showing the expanded integumentary lappets. 



5. Actinal view of a terminal plate and adjacent portion of ray. The actinal terminal spines 



cover the bright red "ocular" organ here shown in solid black. 



238 



