300 SMITHSONIAN INSTITUTION 



genus, and not of Ichthyocrinus. This species added to the one from West Virginia, brings 

 the range of. the genus strongly into the Devonian. 



Type. Peabody Museum, Yale University, New Haven, Connecticut. The original of 

 Plate XXXVII, figures 130, b, was found by the veteran collector Frederick Braun and by him 

 contributed to my collection in aid of this work. 



Horizon and locality. Devonian, New Scotland formation of the Helderbergian ; Clarks- 

 ville and Schoharie, New York. 



(?) Clidochirus greenei (S. A. Miller) 

 Plate XXXVII, fig. 14 



Ichthyocrinus greenei Miller, Geol. Surv. Indiana, Adv. Sheets 18th Rep., 1892, p. 52, pi. 8, fig. 3 (Final 

 Report, 1894, p. 306). — Springer, Jour. Geol. XIV, 1906, pp. 490; (? Metichthyocrinus) 517. 



A large species. Crown elongate, pyriform ; 50 mm. high by 21 mm. wide 

 at widest part, about IIIBn; height to width at IIBn, 1 to 0.8; at I Ax, 1 to 0.9; 

 spread of calyx from base to IIBn, 1 to 2.8; cross-section circular, side outline 

 concave or straight, continuous with stem. Base truncate. Surface smooth. 



IBB large, visible as broad, low pentagons. BB small, wider than high. 

 RR small, about one and one-half times wider than high. IBr and IIBr about 

 twice as wide as high, increasing in width from RR upward; IBr 3; IIBr 4; 

 IIIBr 5 to 10 or more, with other bifurcations following. Rays interlocking at 

 least to upper IIBr, abutting and infolding above, branching to at least 4 bifur- 

 cations ; plates evenly curved, with but little convexity. No interbrachials, anal 

 side unknown. Column large, continuous with calyx, with a proximal enlarge- 

 ment composed of short columnals increasing in length downward as far as 

 preserved. 



This species was founded upon a single specimen, described by S. A. Miller as Ichthyo- 

 crinus. It is said in the description to be from the Keokuk limestone of the Lower Car- 

 boniferous, and no other example of it has been discovered. Three rays are exposed, while 

 the other side of the crown lies imbedded in a coarse, siliceous limestone harder than the 

 fossil, thus effectually preventing any further exposure of the rays by cleaning. Unfor- 

 tunately the part concealed is the posterior side, and we do not know what the anal structure 

 is ; from what can be seen of the calyx there is room for a narrow single series of anals. The 

 large basals and upstanding infrabasals remove it from Ichthyocrinus. 



The aspect of this fossil is nearer that of Clidochirus, to which it would clearly belong if 

 possessing a series of anal plates, except for the number of primibrachs ; in the visible rays 

 this is clearly three, which if constant for the others would separate it from all normal forms 

 of this and related genera. It would then (assuming its recorded horizon to be correct) have 

 to stand as a Carboniferous representative of Clidochirus, requiring the recognition of a new 

 genus bearing the same relation to the former as Taxocrinus to Protaxocrinus — the develop- 

 ment of the rays thus correlating with its stratigraphic position, and being parallel to similar 

 progressions in the other families. The specimen in this respect may be exceptional, and in 

 the absence of further information as to its essential characters it is advisable to place it with 

 doubt, and provisionally, under Clidochirus. 



Type. Formerly in the collection of Mr. George K. Greene, New Albany, Indiana, now 

 in the American Museum, New York. 



Horizon and locality. ( ?) Lower Carboniferous. In the description the unique speci- 

 men is said to be from the Keokuk Group, Muldraugh Hill, Kentucky. There is a possibility 

 that it may have been derived from Niagaran rocks in Jefferson County, Kentucky. Such a 

 geological position would confirm the reference to Clidochirus as a variant. 



