Plate 25. 

 1-6. Dermatodiadema horridum A. Ag. 



1. Small specimen, measuring 7.3 inin. in diameter, seen from the actinal side; Static 



3362. 



2. Actinal system of a specimen measuring 10 mm. in diameter ; Station 3362. 



3. Enlarged view of actinal part of the odd anterior ambulacrum of the same specimen .. 



fig. 2. 



4. Actinal system of a specimen measuring 10.5 mm. in diameter; Station 3363. 



5. Actinal system of a specimen measuring 15 mm. in diameter ; Station 3413. 



6. Lower part of primary interambulacral spine of a specimen measuring 20 mm. : 



diameter ; Station 3413. 



