Plate V. 



From specimens in the author's collection, unless otherwise noted. 



1. Cidaroblastus parvus, n. s., showing one interambulacrum. 



2. Cribroblastus incisus, n. s. 



3. Cribroblastus verrucosus, n. s., showing the interambulacrum. 



4. Globoblastus ornatus, n. s., showing interambulacral space. 

 6. Interambulacrum of Globoblastus spatatus, n. s. 



6. Pentremites turbinatus, n, s., lateral view. 



7. Pentremites bradleyi Meek. — from specimen in the Smithsonian Insti- 

 tution. 



8. Cribroblastus schucherti,n. s., magnified, — from specimen in the Smith- 

 sonian Institution. 



8a. The same specimen, natural size. 



9. Interambulacrum of Cribroblastus sampsoni. 



10. Interambulacrum of Cribroblastus Boemeri. 



11. Interambulacral space of Cribroblastus neglectus. 



12. Interambulacral space of Cribroblastus granulosus. 



13. Interambulacrum of Cribroblastus pisum. 



14. Cribroblastus sayi, — from Shumard's type specimen. 



15. Outline of Cnbroblastus potteri. 



16. Cribroblastus tenuistriatus , n. s. 



17. Interambulacrum of Cribroblastus tenuis, n. s. 

 17a. Outline of specimen, natural size. 



18. Pentremites kirki, n. s., lateral view, — from specimen in the collection 

 of Mr. Kirk. 



