440 MR. F. A. BATHER ON PETALOCRINUS. [Aug. 1 898, 



Fig. 16. (c) From true right side (left side of ventral view) ; showing angle of 

 facet and longitudinal curvature. The distal corner on the 

 other side is broken (see text-fig. 8, c, p. 423). X 4 diam. 



17. (c) Articular facet ; shows axial canal and diverging downwardly- 



directed ridges. X 4 diam. 



18. (d) Articular facet, as in fig. 17 ; shows also apparent slight striation 



of dorsal margin. X 4 diam. 



19. ( j) Proximal end, from true left side, showing angle of facet. 



20. ( j) Articular facet. X 4 diam. {Cf. text-fig. 5, p. 41(3.) 



21. (i) Abnormal facet, with two axial canals, and trace of original suture 



in median ridge. X 6 diam. 



22. (m) Abnormal facet, with four axial canals in a concavity. X 6 diam. 



23. (e) Type. Shagreen ornament on dorsal surface. X 10 diam. 



24. (e) „ A ridge, seen from the side, showing notches for covering- 



plates. X 10 diam. 



25. (p) A ridge, seen from the side, showing flat top and lateral notches. 



X 10 diam. 



Petalocrinus angustus. Type (p. 425). 



Fig. 26. Two ridges, seen from the side, three-quarter view ; notches for 

 covering-plates, x 10 diam. 



27. One ridge seen from above, showing alternation of notches. X 10 diam. 



28. Distal end. {Cf. figs. 3 & 5.) 



29. Distal half, from true left side, showing lines of growth. X 6 diam. 



30. From true right side ; showing flatness of fan. 



31. Yentral view ; the traces of pigment are not shown, for the sake of 



clearness. 



32. Dorsal view, showing growth-lines, shagreen ornament, and depressions 



corresponding with ventral ridges. 



Tetalocrinus expansus. Type (p. 434). 



Fig. 33. Elevation, as seen from the distal end, showing transverse curvature 

 almost flat. 



34. Ventral view {Cf. text-figs. 13 & 14, p. 435). 



35. Articular facet, much worn. 



36. From true left side, to show angle of facet and absence of longitudinal 



curvature. 



Plate XXVI. 



Specimens from Iowa and Indiana, drawn by the Author, with some help 

 from photographs and sketches by J. Green. 



JPetalocrinus mirabilis (p. 427). 



Fig. 37. (f 2) Dorsal view ; the arm-fans arbitrarily numbered i-v. 



38. (d 1) Dorsal view ; the arm-fans arbitrarily numbered i-v. 



39. (dl) Dorsal cup, in the same orientation. X 6 diam. 



40. (k) Dorsal view of an arm-fan ; the dorsal surface removed in parts, 



exposing the cavity of the fossil and the floor of the 

 ventral surface. 



41. (a) Dorsal view ; the arm-fans arbitrarily numbered i-v. Nat. size. 



42. (a) Dorsal view of dorsal cup, in the same orientation, showing 



columnal, IBB, BB, RR, and TBr. x 6 diam. 



43. (a) Dorsal cup, from interradius i-ii ; showing portion of tegmen. 



44. (d 2) An arm-fan from which the dorsal surface laas been removed, 



seen in dorsal view, showing the floor of the grooves, 

 here seen as ridges, and the scalloping of their ends. 



45. (f 1) Ventral view of a wax squeeze taken from the impression of 



the tegmen. For interpretation, see text-fig. 3, p. 409. 

 X 4 diam. 



