2 

 Pentephyllum Adarense, Huughton. 



Page 



Fig. 14. Summit view of an internal cast of this peculiar form, with the radio-deltoid 

 suture faintly visible. Carboniferous Limestone, Ireland. Coll. University 

 Museum, Dublin. Natural size 122 



Fig. 15. Iuterradial view of the same specimen, showing the protuberant base. Natural 



size 296 



Fig. 16. Inferior aspect of the same specimen, showing the regularly trimerous base, and 



the absence of any facet for the attachment of a column. Natural size . . 18 



Tric(elocrinus Meekianus, E. fy C, p. 208. 



Fig. 17. Basal view. Subcarboniferous, Indiana. Natural size 197 



Fig. 18. Radial view of the same specimen. Natural size 204 



The lines which are represented as radio-deltoid sutures are possibly only cracks 

 in the matrix. 



Pentremites Godoni, Defrance, sp., p. 157. 

 Fig. 1 9. Section of an ambulacral field, with the two groups of hydrospires closely appressed 

 to the inner edge of the lancet-plate. The under lancet-plate cannot be differ- 

 entiated. Subcarboniferous, Alabama. x 6 94 



Pentremites sulcatus, Roemer, p. 163. 

 Fig. 20. Section of an ambulacral field, exhibiting the hydrospire-sacs in perspective relief. 



Compare PI. XVIII. Fig. 5. Subcarboniferous, Illinois. x 4 94 



Pentremites hemisfhericus, Humbach. 

 Fig. 21. Summit view, showing the relations of the lancet-plates at the central ends of the 



ambulacra. Subcarboniferous, Illinois. Coll. P. H. Carpenter. x 2 . . 43 



Pentremites Godoni, Defrance, sp., p. 157. 

 Fig. 22. Radial view of a very young specimen winch Mr. C. "Wachsniuth refers to this 



species. Subcarboniferous, Alabama. Cull. Wachsmuth. X 10 .... 159 



Fig. 23. Summit view of the same, exhibiting unusually wide rosette-like ambulacra . . . 159 



