Plate V. 



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



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



2. Cribrohlastus incisus, n. s. 



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



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



5. Interambulacrum of Globoblastus spatatus, n. s. 



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



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

 tution. 



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

 sonian Institution. 



8a. The same specimen, natural size. 



9. Interambulacrum of Cribrohlastus sampsoni. 



10. Interambulacrum of Cribrohlastus Boemeri. 



11. Interambulacral space of Cribrohlastus neglectus. 



12. Interambulacral space of Cribrohlastus gramdosus. 



13. Interambulacrum ot Cribrohlastus pisum. 



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



15. Outline of Cribrohlastus potteri. 



16. Cribrohlastus tenuistriatus, u. s. 



17. Interambulacrum of Cribrohlastus tenuis, u. s. 

 17a. Outline of specimen, natural size. 



18. Pentremites kirki, n. s., lateral view, ^ from specimen iu the collectiou 

 of Mr. Kirk. 



