176 SMITHSONIAN INSTITUTION 



Asaphocrinus ornatus (Hall) 

 Plate IV, figs. 1-22 



Cyathocrinus ? Hall, Nat. Hist. New York, Geol. 4th Dist. 1843, tab. 21, figs. 4, 4a. 



Lecanocrinus ornatus Hall, Nat. Hist. New York, Pal. II, 1852, p. 201, pi. 44, figs. 2a-m. — Wachsmuth 



and Springer, Revision Palaeocrinoidea, pt. 1, 1879, p. 40. — Springer, Jour. Geology, XIV, 1906, 



p. 501. 

 Lecanocrinus nitidus Ringueberg, Bull. Buffalo Soc. Nat. Hist., V, 1886, p. 9, pi. I, fig. 5. 



A variable species. Specimens small. Crown elongate, average height to 

 width at I Ax about 1 to 1. Calyx low, cup-shaped, differentiated but little or 

 not at all, spreading gradually to top of RR, where height to width in an average 

 of ten specimens is I to 1.5. Side outline curved. Anal tube but slightly de- 

 veloped. Surface in well-preserved specimens ornamented with fine pustules; 

 this ornament is very rarely seen, most specimens appearing perfectly smooth. 

 A maximum crown with arms extended is 23 mm. high by 12 mm. wide, and 

 8 by 12 at top of RR; base at column facet, 3 mm. 



IBB fairly large, usually forming a low cup. BB large. RA small. Anal 

 x large, truncate or indented above, surmounted by a rounded, longitudinal 

 ridge; followed by one or more plates in series continuous with the ridge, bor- 

 dered by small plates at one or both sides which are not often exposed. RR rela- 

 tively smaller than BB, not over twice the length of succeeding IBr. IBr 2, 

 large. Height of B to R to IBr, as 4 : 3 : 1.5. IIBr 3 to 5 ; IIIBr 5 to 10, followed 

 usually by one more bifurcation. Rays rounded, with narrow open spaces be- 

 tween them and their divisions for lodgment of perisome; diminishing rapidly 

 and rather suddenly beyond the third bifurcation into fine, threadlike terminals. 

 Column strong and short, terminating in a branching root for attachment to 

 other bodies ; it tapers very gradually from the calyx to the end ; a few proximal 

 columnals are usually thin and tapering, especially in young specimens, followed 

 by strong alternation of long curved ossicles with shorter ones, all becoming 

 uniform half way down. 



Hall described this species from the Rochester shale at Lockport in 1852, and called 

 attention to the difference in habitus of the rays and arms from that of his other species of 

 Lecanocrinus. Dr. Ringueberg afterwards found a number of better specimens in the same 

 shale, from among which he described three species, viz., L. nitidus, L. excavatus, and 

 L. incisus. All this material is now in my possession, reinforced by further accessions from 

 my own collections since made, amounting to a total of about 60 specimens in various posi- 

 tions from those with arms closely folded to widely spread. All are from a small area in the 

 same horizon as the type — the lower part of the shale — and with slight variations largely due 

 to difference in the manner of preservation and maturity of the specimens there is a general 

 similarity of habitus. Many of them are more or less flattened, but a restoration of Hall's 

 principal type, made from the specimen by accurate measurements, gives a contour about the 

 same as that of figures 20 and 21 of Plate IV, which are but little compressed. Some have 

 the arms folded at about the third bifurcation, and others have them extended, which gives 

 them a different appearance but the essential characters remain the same. I am unable to dis- 

 tinguish the type of L. nitidus (PI. IV, fig. 22) from average specimens of L. ornatus. The 



