Plate 111. 



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



1. Cidaroblastus granularis, — loaned by G. K. Green. 



2. Lateral view of same species, — Troost Collection, Smithsonian Institu- 

 tion, No. 33080. 



3. Summit view of same. 



4. Cidaroblastus globosus, — Troost Collection, Smithsonian Institution, 

 No. 33077. 



5. Globoblastus magnijiciis. 



6. 7. Lateral and basal views of Pentremites sulcatits, showing an elongated 

 piece inserted between two fork pieces. 



8, 9. Pentremites pyriformis, showing an undeveloped fork piece and 

 ambulacrum. 



10. Pentremites sulcatus, showing a crippled ambulacrum. 



11, 12. Pentremites sulcatus, with only four ambulacra developed and a 

 fifth fork piece solid. 



13, 14. Pentremites sulcatus, with only four ambulacra. 

 15, 16. Pentremites pyriformis, with six fork pieces but only four ambu- 

 lacra developed. 



17. Saccoblastus, with five fork pieces but six ambulacra, of which two 

 occupy one sinus. 



18. Pentremites godoni, with four fork pieces but with five ambulacra, of 

 which two occupy one sinus. 



