ICHTHYOCRINIDAE 28l 



are strongly expressed by the shortness of the rays, which have but a single bifurcation ; the 

 larger base and consequent ovoid instead of pyriform crown; and by the stem with its long 

 non-alternating columnals. Upon such a specimen Hall proposed his Lecanocrinus simplex. 

 None of the specimens show any trace of surface ornamentation in the sense mentioned in 

 the generic description. 



Types. The facts as to these are given above. The originals of Hall's figures 2b and 2c, 

 Pal. New York, plate 43, are in the American Museum of Natural History, New York. 

 Except where otherwise stated the remaining specimens used in the illustrations are in my 

 own collection. Those with stems attached were collected many years ago by Dr. Ringueberg 

 of Lockport, and passed into my hands with the rest of his rare collection of the crinoids of 

 that region. 



Horizon and locality. Silurian, the species is confined to the Niagaran group of western 

 New York and Canada, and has only been found in the Rochester shales. All the known 

 specimens have come from Lockport, New York and Grimsby, Canada. 



Ichthyocrinus subangularis Hall 

 Plate XXXIV, figs, i-io 



Ichthyocrinus subangularis Hall, Adv. Abstract Trans. Albany Inst., 1863, p. 7 ; Trans. Albany Inst., IV, 

 1864, p. 201 ; Adv. Pub. 18th Rep. New York St. Cab. Nat. Hist., 1865, p. 21, pi. 2, figs. 15, 16; ibid., 

 20th Rep., Doc. Ed., 1867, pp. 325, 384, pi. 11, figs. 15, 16; Rev. Ed., 1870,'pp. 367, 429, pi. n, figs. 15, 

 16; ibid., 28th Rep., 1879, P- T 37. pi- 16, figs- n, 12, 13; nth Rep. St. Geol. and Nat. Hist. Indiana, 

 1882, p. 268, pi. 15, figs. 12, 13; pi. 16, figs. n-13. — Wachsmuth and Springer, Revision Palaeocri- 

 noidea, pt. 1, 1879, p. 35. — Miller, Jour. Cin. Soc. Nat. Hist., IV, 1881, p. 175; sep. p. 10; N. A. Geol. 

 and Palaeontology, 1889, p. 256. — Weller, Bull. 4, Chicago Acad. Sci. 1900, I, p. 146, pi. 15, figs. 3-5. — 

 Springer, Jour. Geology, XIV, 1906, p. 477, pi. 6, fig. 2. 



A large species. Crown elongate, narrowly turbinate or obconic below the 

 widest part, contracting into a distinct neck at the base next to column facet; 

 subangular from radials up owing to median elevation of the brachial series; 

 base truncate; height to width at upper IIBr, about I to i.i; spread of calyx 

 from RR to same level, about i to 2.4. Side outline of calyx slightly convex; 

 cross-section at- IIBr subpentangular. Plates but little imbricated; surface 

 smooth. Lower calyx plates very thin. Maximum crown, 70 mm. high to I VBr 

 by 43 mm. wide at about JIIBr 4 , the arms not being -complete ; base of average 

 specimen, 7 mm.; complete crown of smaller size, 31 by 18 mm.; width of 

 base, 5 mm. 



IBB small, covered by the column. BB larger than in any other species, 



well exposed in pentagonal outline, but lower angles concealed by the column; 



salient angles rather long. Brachials with obtusely angular longitudinal median 



ridge, prominent in the first and second series, diminishing upward. IIBr 



usually 4. Average height to width of IBr, about 1 to 1.8; of IIBr, 1 to 2.4. 



HIBr 6 to 10, with another bifurcation visible. Column unknown. 



The history of this species and its relations to /. corbis are more particularly set forth 

 under that species. It is a rare fossil at its typical locality, Waldron, Indiana, where it occurs 

 in the Waldron shales of the Niagaran group. I have referred to it specimens from the 

 Racine dolomite beds at Chicago, and from the Rochester shales at Lockport, New York. 

 It is possible that some of these belong to distinct species, but upon any diagnostic characters 



