PLATE XVIII. 



Pourtalesia miranda. 



1. Seen in profile, magnified 3.5 in diam. 



2. Same seen from actinal side. 



3. Same seen firom abactinal side. 



4. Same seen endways from the anterior extremity. 



5. Posterior extremity, seen in profile, somewhat more magnified than preceding fig. 



6. Posterior extremity, seen from the abactinal side. 



7. Posterior extremity, seen obliquely from above to show anal opening. 



8. Anterior extremity seen obliquely to show actinostome and odd anterior ambulacnim. 



9. Magnified view of abactinal system, with expanded tentacles. 



10. One of the long slender spines greatly magnified. 



11. Imperforate crenulated tubercle, with broad scrobicular circle, carrying large spines. 



1 2. Base of large spine seen in profile with attachment. 



13. Base of large spine, with tubercle, showing mode of attachment to scrobicular circle. 



14. One of the small flattened short spines of test, greatly magnified. 



15. Extremity of one of the smaller fan-shaped spines like fig. 10, magnified. 



16. Extremity of one of the large tridactyle pedicellariic, fully expanded, in profile. 



1 7. Same from above. 



18. Same contracted, from above. 



19. A couple of the large tentacles of the odd anterior ambulacrum, magnified. 



