48. 



(c) 



49. 



(c) 



50. 



(c) 



51. 



(1) 



52. 

 53. 

 54. 

 55. 



(1) 

 (1) 

 (1) 

 (1) 



Vol. 54.] MR. P. A. BATHER ON PETALOCRINUS. 441 



Fig. 46. (f 1) Dorsal Tiew of a crown from which the dorsal cup has been 

 removed. The arm-fans show the floor of the grooves as 

 ridges. A portion broken away in arm -fan ii exposes 

 impressions of covering-plates. Nat. size. 

 47. (f 1) Ventral view of a was squeeze taken from the impressions 

 of ridges and covering-plates beneath the broken portion 

 of arm-fan ii. The grooves are exposed in the upper 

 part of the drawing, but hidden by covering-plates in its 

 luwer part. X 8 diam. (See p. 416.) 



Joint-surface of a columnal showing minute lumen in a slight con- 

 cavity, and subpentagonal bevelling of edges. X 6 diam. 



Joint-surface of a columnal, striated, with lumen more definite 

 than in fig. 48. X 6 diam. 



Side view of three columnals, showing the crenulation of the 

 sutures. X 6 diam. 



Distal end, ventral surface upwards ; shows considerable in- 

 dentation of the median ridge. 



Ventral view. 



Articular facet. X 4 diam. 



From true right side. 



A ridge from above, showing notches for covering-plates. 

 X 10 diam. 

 56. (1) Two ridges from the side, three-quarter view. X 10 diam. 



Tetalocrinus inferior (p. 426). 

 Fig. 57. Type. The impression of the ventral surface. {Cf. text-fig. 10, p. 427.) 



Tetalocrinus longus. Type (p. 431). 



Fig. 58. Dorsal view. Nat. size. 



59. Articular facet, showing double axial canal. X 4 diam. 



60. Ventral view. {Cf. text-figs. 11 & 12, p. 432.) 



61. A ridge from above, showing notches for covering-plates. X 10 diam. 



62. Two ridges from the side, three-quarter view. X 10 diam. 



63. Distal view of perfect upper corner of the fan, showing axial canals. 



X 4 diam. 



64. Ventral view of perfect distal corner of the fan, showing axial canals 



emerging. X 6 diam. 



65. From true left side, showing angle of facet and slight longitudinal 



curvature. 



Discussion. 



Dr. G. J. HiNDE complimented the Author on the very successful 

 manner in which, with such imperfectly preserved materials, he had 

 elucidated the structural characters and affinities of this peculiar 

 genus of crinoids. An examination of the specimens exhibited 

 satisfactorily confirmed the interpretations given of them by the 

 Author. 



Dr. H. VyooDWART) also spoke. 



The Author thanked the Fellows for their reception of his paper, 

 and was glad to find that it met with the approval of those who 

 had overcome similar difficulties. He drew attention to another 

 specimen exhibited by him, the first Silurian crinoid from Australia, 

 named Hapalocrinus Victorice, and lent by Mr. T. Hall, of 

 Melbourne Universitv. 



