EEPOET ON THE ECHINOIDEA. 283 



Fig. 3. Coronal plates of abactinal surface near lower part of test (f ). 

 „ 4. Coronal plates of actinal surface (f-). 

 „ 5. Coronal plates of abactinal surface, somewhat above the plates of fig. 3 (f). 



Micropyga tuherculata, A. Ag. (figs. 6, 7), p. G8. 

 „ 6. Abactinal system of young specimen, measuring 8 mm. {^^). 

 „ 7. Actinal system of same (i?). 



Trigonocidaris monolini, A. Ag. (figs. 8-10), p. 111. 



„ 8. Actinal system of specimen measuring 8 mm. in diameter {'^^). 

 „ 9. Abactinal system of same (ij2). 



„ 10. Plates of the abactinal surface of the test immediately above the ambitus of 

 same. 



Prionechinus sagittiger, A. Ag. (figs. 11 14), p. 109. 



„ 11. Specimen measuring 7 mm. in diameter, covered with spines, seen from the 



abactinal side. 

 „ 11 a. Magnified primar}^ spine. 

 „ 12. Actinal system of same (\2). 

 ,, 13. Abactinal system of same. 

 „ 14. Coronal plates of test above ambitus of same. 



Cottaldia forhesiana, A. Ag. (figs. 15-17), p. 112. 



,, 15. Coronal plates of test above ambitus, same as fig. 16. 



,, 16. Abactinal system of specimen measuring 17 mm. in diameter. 



,, 17. Magnified primary spine. 



PLATE VII. 



Micropyga tubercidata, A. Ag. (figs. 1-9), p. 68. 



Fig. 1. Seen from the abactinal pole ; natural size. 

 „ 2. Same, seen from the actinal side. 

 ,, 3. Magnified view of the actinal cuts. 

 „ 4. Magnified view of portion of interambulacral and ambulacral zones of the actinal 



side. 

 „ 5. Magnified view of portion of iuterambulacraland amlmlacral zone of the abactinal 



side. 

 „ 6. Magnified view of denuded abactinal system. 



