AMERICAN SILURIAN CRINOIDS 
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Zophocrinus howardi S. A. Miller 82 
Figs. 19, 20. Posterior and anterior views of two specimens with the marginal ring of brachials and 
orals in place. X 4- 
21. Ventral view of another specimen in which the spade-shaped oral plates are very dis- 
tinct, but somewhat frayed and displaced by pressure. X 4- 
2ia. The same tegmen further enlarged, showing fossae on articulating face of some brachials. 
X8. 
22. Complete view of tegmen, composed from two other specimens. Shows the 4 radii, and 
division of tegmen into S oral plates interlocking at the center, and extending to the 
periphery, with marginal plates between in 5 groups of 3 each. X 6. 
23. Base of another specimen, showing 3 unequal plates. 
24. Calyx of a maximum specimen. 
25. Specimen from Greenburg, Indiana. 
26. Specimen from Flatwoods, Tennessee. 
Laurel formation, Niagaran; all from St. Paul, Indiana, except Nos. 25 and 26. 
Tiaracrinus quadrifrons Schultze 81 
Fig. 27. Post, view of type, with the numerous marginal brachials bordering the tegmen in place, 
showing the same essential structures as Zophocrinus, but with a minute base. 
27a, Basal view of same, showing the 4 unequal radii, and 3 minute BB. 
27b. The same view, further enlarged. X 6. 
27c. The tegmen. Five interlocking oral plates meeting in the center, with narrower exten- 
sions to the outer margin, and some smaller plates inserted at the exterior angles ; the 
posterior oral wedged in between the other 4. Surrounding these is the border of 
narrow marginal brachials in 5 groups of ii or 12 each, instead of 3 as in Zopho- 
crinus, separated by the extensions from the oral plates. X 4- 
Middle Devonian; Eifel, Germany. 
Haplocrinus mespiliformis (Goldfuss) 50,81 
Fig. 28. Ventral view of specimen showing the interlocking orals and radial grooves for the 
reception of the arms, as usually seen. X S- 
29. A specimen with arms preserved to 3 brachials fitting closely in the grooves between the 
orals. X 5- 
29a. Ventral view of same, showing the open grooves in 2 radii. X 5- Figured here for 
comparison. 
Middle Devonian; 
Eifel, Germany. 
