LECANOCRINIDAE 



I2S 



LECANOCRINUS Hall 

 Plates I-III 



Lccanocrinus Hall, Nat. Hist. New York, Pal. II, 1852, p. 199.— Pictet, Traite Palaeontologie, IV, 1857, 

 p. 319. — Bronn, Klassen u. Ord. Thier-Reichs, II, i860, p. 231. — Schultze, Mon. Echinodermen 

 Eifler Kalkes, 1867, p. 40. — Beyrich, Monatsber. Akad. Wiss. Berlin, 1871, p. 42 (Transl. in Ann. 

 and Mag. Nat. Hist., (4) VII, p. 403— Quenstedt, Petref. Deutschlands, IV, 1876, p. 516.— Angelin, 

 Icon. Crin. Sueciae, 1878, p. 11. — Von Zittel, Handbuch Palaeontologie, 1879, pp. 343, 355; Grund- 

 ziige Palaeontologie, 1895, p. 138. — Wachsmuth and Springer, Revision Palaeocrinoidea, pt. 1, 

 1879, p. 39; Proc. Acad. Nat. Sci. Philadelphia, 1890, p. 388.— Oehlert, Bull. Soc. Geol. France 

 (3)X, 1882, p. 354. — Miller, N. A. Geology and Palaeontology, 1889, p. 257. — Zittel-Eastman, Text- 

 book Palaeontology, 1896, p. 163 (2d Ed. 1913, p. 203). — Bather, Rep. British Assoc, for 1898 

 [1899], p. 923; Treatise on Zoology (Lankester), pt. 3, 1900, p. 188. — Weller, Bull. 4, Chicago 

 Acad. Sci., VII, 1900, p. 147. — Springer, Amer. Geologist, XXX, 1902, p. 94; Jour. Geology, XIV, 

 1906, pp. 491-501. 



Cyrtidocrinus Angelin, Icon. Crin. Sueciae, 1878, p. 20. — Wachsmuth and Springer, Revision Palaeoc- 

 rinoidea, pt. 3, 1886, p. 144. 



Fig. 12. Lecanocrinus 



Lecanocrinidae with rays in contact except at anal side. Crown short and 

 ovoid, main expansion in zone of radials ; calyx well differentiated. Inf rabasals 

 usually more or less erect forming part of the calyx wall. Radianal rhombic, 

 obliquely to lower left of right posterior radial, resting on basals, not touching 

 right anterior radial. Anal x alone, filling posterior interradius; no inter- 

 brachials in other areas. Primibrachs two, exceptionally one. Arms dichoto- 

 mous, interlocking. Column not enlarging proximally, or but little; columnals 

 usually alternating from the top, becoming uniform farther down. 



Genotype. Lecanocrinus macropetalus Hall. 



Distribution. Silurian and Devonian ; Continental Europe, England, and 



North America. 



Lecanocrinus is the type of its family, having usually a short, ovoid crown, with base 

 well developed, both infrabasals and basals more or less erect forming an important part of 

 the calyx wall. The chief expansion is in the proximal region of the crown, producing the 



