REVIEW OF OPHIODERMA 187 



4. Arm-spines 7 or less 5 



4. Arm-spines 8 or more 6 



5. Arm length 4 to 5 times disk diameter. Disk grains excessively 

 large, flat, tile-like ; no exposed scales on disk. West Indies . . 



3. squamosissimum Lutken 



5. Arm length 3 times disk diameter. Granules small, round ; a few 

 disk scales may be exposed ; a few upper arm plates may be fused 

 into one piece. Locality doubtful ; South Africa 



4. wahlbergii* Miiller & Troschel 



6. Arms short, about ZVz times disk diameter, arms never banded. 

 Panamic 



5. teres (Lyman) 



6. Arm length 3^^ times disk diameter, or more 7 



7. Arm length 3^^ times disk diameter, arms banded. West Indian 



6. cinereum Miiller & Troschel 



7. Arm length 4^^ times disk diameter, arms not banded. East 

 Atlantic 



7. longicauduTti (Retzius) 



8. Radial shields normally exposed ; sometimes partly covered in 

 phoenium and pananiense 9 



8. Radial shields covered by disk granulations 12 



9. Arm-spines 9, rarely 10 10 



9. Arm-spines 10 to 12 11 



10. Upper arm plates narrow, arms 4 to 5 times disk diameter, oral 

 shields large, sub-cordate. Havana. 110 to 200 fathoms . . . 



8. pallidum* (Verrill) 



10. Upper arm plates broader than long, arm length 3 to 4 times 

 disk diameter. Atlantic 



9. phoenium H. L. Clark 



11. Adoral shields concealed; 10 to 12 arm-spines, arms banded. 

 Panamic 



10. panamense Lutken 



11. Adoral shields exposed, 10 arm-spines. Atlantic 



11. ruble undum hiitken 



12. Adoral shields exposed 13 



12. Adoral shields not exposed 19 



13. Five arm-spines, rarely 6. Panamic 



12. pentacanthum H. L. Clark 



13. Seven arm-spines or more 14 



14. Lowermost arm-spine largest 15 



14. Arm-spines of equal size 16 



