LECANOCRINIDAE 131 



IBB protuberant, very large, forming a truncate cone. BB large. Anal x 

 high, acute-angular, extending for one-half its height above the radials. RR 

 proportionally small, not over twice the height of IBr; height of B to R to IBr, 

 6:5:2.5. IBr 2; IIBr 3 in all rays visible; IIIBr 6 to 9. Arms bifurcating again 

 before infolding; rather flat and tapering but little. Column large, as wide as 

 the truncate base ; with strong alternation of long and short ossicles beginning 

 at the proximal end and continuing for more than 20 long nodal columnals with 

 short internodals interposed. 



This species is represented by a single specimen, no other except Dr. Ringueberg's type 

 having been found ; but that is a remarkably fine and perfect one. While its relative dimen- 

 sions at the upper primibrach are about the same as those of L. macropetalus, the outline of 

 the calyx is altogether different, and the proportions of the infrabasals, radials, arms and 

 column give it quite another aspect from that species. It was found in the lowest of the 

 shales at Lockport, therefore below the zone of L. macropetalus. 



Type. Author's collection. 



Horizon and locality. Silurian, lower third of Rochester shale ; Lockport, New York. • 



Lecanocrinus pusillus (Hall) 

 Plate I, figs, 1-13 



Cyathocrinus pusillus Hall, Adv. Abstr. Trans. Albany Inst., IV, 1863, p. 6; Final Rep., 1864, p. 200; 



Prelim. Notice 18th Rep. N. Y. St. Cab. Nat. Hist., 1865, p. 20; 20th Rep., 1868, p. 324; Revised 



Ed., 1870, p. 366. — Shumard, Trans. Acad. Sci. St. Louis, II, 1866, p. 363. 

 Lecanocrinus pusillus Hall, 28th Rep. N. Y. St. Cab. Nat. Hist. (Doc. Ed.), 1876, expl. of plate 15 



(Mus. Ed., 1879, p. 136, pi. IS, figs. 1-6) ; nth Rep. Geol. Nat. Hist. Indiana, p. 267, pi. 14, figs. 



1-6; pi. IS, fig. 7. — Wachsmuth and Springer, Revision Palaeocrinoidea, pt. 1, 1879, p. 40. — 



Weller, Bull. 4, Chicago Acad. Sci., pt. 1, 1900, p. 148, pi. i'S. — Foerste, Bull. Geol. Soc. America, 



XII, 1901, p. 443; Jour. Geology, XI, Oct.-Nov., 1903, pp. 708, 712. 

 Lecanocrinus Tennesseensis S. A. Miller, Adv. sheets 17th Rep. Geol. Surv. Indiana, 1891, p. 41, pi. 7, 



figs. 7, 8; Final Rep., 1892, p. 651. 



A medium-sized species. Crown subglobose, widest at IAx where height 

 to width is 1 to 1.3; average height to width of 15 specimens at top of RR, 1 to 

 1.65 ; base rounded. A complete crown is 19 mm. high by 15 mm. wide at top of 

 IAx; maximum calyx, 10 mm. high by 16 mm. wide at RR; width at column 

 facet, 3.5 mm. ; minimum calyx, 5 by 9. Calyx walls thick. Surface ornamented 

 with fine raised granules, often coalescing into a wrinkled lace-work. 



IBB large, usually following the curvature of adjoining plates; visible in 

 side view, and often protuberant. BB large. Anal x short and wide (almost 

 as wide as high), projecting half its length above the radials. RR large, about 

 two and one-half times the height of primibrachs; average height of B to R to 

 IBr, 5:5:1.5. IBr 2 ; IIBr 3 or 4, with another bifurcation visible. Rays closely 

 abutting, sides about parallel; arms flat, longer than in L. pisiformis, and not 

 tapering so rapidly. Column facet shallow, saucer-shaped. Column rather large, 

 composed from the top down of wide and conspicuous rounded nodal columnals, 

 with narrow internodals regularly intercalated. 



