ARCHEAN AND PALEQZOIC LIFE 421 
PLATE 20. 
A group of Carboniferous crinoids. 
(1, Megistocrinus evansi; 2, Archimedes reversa (a bryozoan); 3, Pentremites 
melo; 4, Pentremites cherokeus; 5, Actinocrinus unicornis; 6, Scaphiocrinus 
scoparius; 7, Onychocrinus exculptus; 8, Poteriocrinus decadactylus ; 9, Ac- 
tinocrinus ramulosus; 10, Actinocrinus lowi; 11, Actinocrinus nashville. 
