414 SMITHSONIAN INSTITUTION 



Parichthyocrinus meeki (Hall) 

 Plate LXII, figs. 1-3 



Forbesiocrimts meeki Hall, Geology Iowa, I, pt. 2, 1858, p. 631, pi. 17, fig. 3. 



Onychocrinus meeki, Meek and Worthen, Geol. Surv. Illinois, II, 1866, p. 243. 



Taxocrinus meeki, Wachsmuth and Springer, Revision Palaeocrinoidea, I, 1879, P- 49- 



Not Forbesiocrimts meeki, Quenstedt, Handbuch Petrefaktenkunde, 1885, pi. 75, figs. 24, 25 (= Taxocrinus 

 eolletti White). 



Not Taxocrinus meeki, Von Zittel, Grundziige Palaeontologie, 1895, p. 138, fig. 273 ; Zittel-Eastman, Text- 

 book Palaeontology, 1896, p. 164, fig. 273 (= Taxocrinus eolletti White). 



A very large species. Generally similar to P. nobilis, except that the 

 crown is relatively shorter and wider, the average of height to width of four 

 specimens being 1 to 1. 1, and the rays and arms are more prominent and convex, 

 and the regular basals seem smaller, being scarcely visible beyond the column; 

 also the column is more uniform, with non-alternating columnals. Calyx 

 spreading almost horizontally, like a low saucer ; height to width, 1 to 5 ; 

 spread from column to IAx, 1 to 3 ; dimensions of mature specimen : crown, 

 height 43 mm. ; width 50 mm. ; base at column facet, 1 1 mm. 



This species occurs at the base of the Keokuk limestone. Four good specimens have 

 come into my hands supplementary to the type. Three of these, including the two fine 

 specimens figured, were found by the late Lisbon A. Cox at a single locality a few miles 

 north of Keokuk, in a limestone intercalated between chert bands, which he considered to 

 be really at the top of the transition bed, just underlying the true Keokuk ; the fourth was 

 found in exactly the same horizon at the upper end of the exposure at Nauvoo. It there- 

 fore occupies a definite horizon entirely distinct from those of the other species. It is 

 readily distinguished from P. nobilis by the convexity of the rays and their divisions, which 

 gives it a notably different habitus. The calyx is extremely low, almost horizontal ; the 

 unrivaled specimen shown in figures 2a, b — one of the finest crinoids ever found in the 

 Keokuk limestone — shows substantially the natural contour of the crown, being only a 

 little compressed laterally ; and the same very low calyx appears in all the other specimens. 

 The IBB are always, and BB mostly, covered by the column, except post. B. The distribu- 

 tion of iBr is very similar to that in P. nobilis: two or three large plates in succession, or 

 the second and third ranges broken up into smaller plates not materially increasing the width 

 of the area. The 3 IIBr seem to be almost constant. The left posterior radial is usually 

 reduced in size, as well as the right. 



There has been much confusion in the literature regarding this species, partly due to 

 its poor illustration. Hall's figure gave little idea of the anal side, which I have made clear 

 by additional preparation (fig. 1). Comparison of this figure with those of other specimens 

 leaves not the least doubt of their identity ; Meek, who had the type before him, saw that it 

 did not belong to Forbesiocrinus (Geol. Illinois, vol. 2, p. 243), and correctly pointed out 

 the generic distinction that must be based upon the anal structure, referring it upon that 

 ground to Onychocrinus. The " five other individuals of this species " mentioned in the 

 above discussion were specimens of the common Crawfordsville Taxocrinus, labeled 

 meeki in Professor Worthen's collection. This misidentification was made by Hall when 

 describing some crinoids from that locality for his paper in 1861 ; it was accepted by the 

 collectors, and thus the name as attached to an entirely different fossil was distributed by 

 their labels among many museums of the world. Then Quenstedt and Von Zittel published 

 figures of good specimens of the Crawfordsville species under this name, so that the errone- 

 ous reference became currently established in the literature ; this will now have to be cor- 



