284 THE VOYAGE OP H.M.S. CHALLENGER. 



Fig. 7. Interambulacral and ambulacral zones of a smaller specimen (natural size) from 

 the abactinal side. 

 „ 8. Same, seen from the actinal side. 

 „ 9. Abactinal system of same specimen magnified. 



PLATE VIII. 



Aspidodiadema tonsiim, A. Ag. (figs. 1-9), p. 6G. 

 Fig. 1. Seen from the abactinal side (f ). 

 „ 2. Same species seen in profile, slightly enlarged. 

 „ 3. Same as fig. 2, seen from the actinal side, slightly enlarged. 

 „ 4. Denuded specimen, measuring 16mm. in diameter, seen from the abactinal 



pole, to show the anal plates. 

 ,, 5. Same, as fig. 4, seen in profile. 



,, 6. Anal system of another specimen, showing anal plates covered with miliary spines. 

 7. Enhirged actinostome of fig. 1. 



jj 



8. Enlarged view of fig. 5, facing the median interambulacral line. 



„ 9. Enlarged view of same facing the median ambulacral line. 



Aspidodiadema microtuberculatum, A. Ag. (figs. 10-16), p. 65. 



10. Profile of a specimen covered with spines ; natural size. 



11. Enlarged view from actinal side, denuded (26 mm. in diameter). 



12. Same, seen from the abactinal pole. 



13. Enlarged view of genital ring. 



14. Enlarged view of actinostome. 



15. Enlarged view of actinostome actinal membrane denuded to show the size of 



the buccal plates. 

 „ 16. Enlarged view of primary interambulacral tubercles, with a portion of the 

 included ambulacral area. 



PLATE IX. 



Phormosoma luculentum, A. Ag. (figs. 1-2), p. 97. 

 Fig. 1. Seen from above ; natural size. 

 ,, 2. Seen in profile. 



PLATE X. 



Phormosoma luculentum, A. Ag. (figs. 1-4 a,h,c), p. 97. 

 Fio;. 1. Seen from the actinal side ; natural size. 



