Plate 1. 



1-12. Podophora pedifera Agass. 

 1-11. Cystacanths from a specimen 82 mm. in diameter, including the spines. 



1. Left posterior ambulacrum, actinal side, showing a group of cystacanths. 



2. Expanded cystacanth, 0.92 mm. 



3. Side view, of another specimen, 0.92 mm. 



4. Seen from above, specimen of 0.90 mm. 



6. Less developed with only three cysts, 0.66 mm. 



6. Another stage with three cysts, 0.60 mm. 



7. Showing the mode of attachment of the cysts to the spine, 0.71 mm. 



8. Profile of cystacanth of 0.54 mm. 



9. Same, front view. 



10. Side view of one of the smallest cystacanths with three cysts, 0.41 mm. 



11. The same, rear view. 



12. Pedicellaria, to show its comparative size to the cystacanths. 



All the figures equally magnified, measurements indicate the natural size of the sacs 

 ■without the spine. 



