INDIANA PALEONTOLOGY. m. 



There are four arm bases to the ray or twenty arms in all. 



A delicate thread-like elevation traverses the radial series, bifurcating on 

 the second costal and again on the second distichal. A slight basal concavity 

 involves the plates to the top of the radials (first radials). 



The specimen is from the Warsaw Limestone of Edwardsville, Ind., and is 

 the property of Mr. G. K. Greene. 



TRIC^LOCRINCS WOODMANI? M. <k W., Rowley. 



Plate 57. Figs. 5, 6, 7, 8. 



There is some doubt of the correctness of this reference, but it is the same 

 form referred to that species by Etheridge & Carpenter in the "Catalogue of 

 the Blastoidea in the British Museum," plate XIX, figures 13, 14, 15, 16. 



There is no doubt that this form is Roemer's T. ohliquatus and that a well 

 preserved specimen of that form, as indicated by the great plates occasionally 

 found would be as large as Meek <k Worthen's type of T. icoodmani, but T. oh- 

 liquatus described from detached plates alone must give way to M. & W.'s 

 species. In our opinion Etheridge & Carpenter's T. meeki. is a young individ- 

 ual of the form we have here figured, and the species is not valid. 



Our figure 9 is a medium size specimen of Tricmlocrinus {Jfe tablet si us) hi- 

 j)yramidaUs irom the type locality for comparison with T. icoodmani. It is 

 quite evident that the forms can not be separated generically. The three basal 

 depressions are present on both forms and the only apparent difference is in 

 the expansion of body below the ambulacral tips. Large, well preserved speci- 

 mens of Metahlastusf wortheni differ not more from hipyramidalis than the 

 latter from icoodmani. 



Keyes has figured on plate XVIII of the "Missouri Geological Survey," 

 volume IV, two adult forms from Booneville, which he identifies as M. irorth- 

 £ni and Jf. hipyramidalis. No collector who has seen a set of the Boonville 

 fossils can separate the forms, as there are scarcely any two of them with the 

 same ambulacral length and, moreover, all the young specimens are elongate 

 and not unlike M. lineatus of the Burlington. Unless lineatus is sufficiently 

 distinct, Metahlastus will have to be abandoned. 



Such forms as Troostocrinus nitidulus and Triccelocrimis varsouviensis 

 are but the young of hipyramidalis, icortheni or icoodmani. 



Meek & Worthen's Triccelocrinus ohliquatus as figured in the VII volume, 



