1885.] NATURAL SCIENCES OF PHILADELPHIA. 321 



Arms stout, long, simple ; composed of a single series of quad- 

 rangular plates, which give off alternately strong pinnules. Col- 

 umn large ; cylindrical. 



The type of the genus, and only known species is : 



*1883. Ehaphanocrinus subnodosus (Walcott), Glyptocrinus (?) subnodosus, 35th 

 Rep. N. York State Mus. Nat. Hist., PI. 17, fig. 3. — Trenton limest. Tren- 

 ton Pall, N. Y. 



LYRIOCRINUS Hall. 



(W. and Sp., Revision II, p. 203.) 



Not Lyrioerinus S. A. Miller, 1882, Journ. Cincin. Soc. Nat. Hist., 

 vol. v, p. 217. 



(?) SAGENOCRINUS Angelin, Rev. II, p. 201. 

 RHIPIDOCRINUS Beyrich, Rev. II, p. 205. 



THYLACOCRINUS Oehlert, Rev. II, p. 207. 



1879. Thylacocr. Vanniosti Oehlert, Extr. du Bull. Soc. Geol. de France 

 (Ser. 3), vii, PI. i, fig. 1 ; also 1882, ibid. vol. x, p. 359, fig. 1.— De- 

 vonian. St. Germain, France. 



ANTHEMOCRINUS W. and Sp. Rev. ii, p. 208. 



RHODOCRINUS Miller, Rev. ii, p. 209. 



1882. Rhodocr. coxanus Worthen, Bull, i, Illinois St. Mus. Nat. Hist., p. 

 80 ; also Geol. Rep. Illinois, vii, p. 305. — Keokuk limest. Keokuk, 

 Iowa. 



OLLACRINTJS Cumberland, Rev. ii, p. 213. 



Family III.— GLYPTASTERID^ W. and Sp. 



PTYCHOCRINUS nov. gen. 

 (jrruj a fold; Kpivov a lily). 



Mr. S. A. Miller has arrayed a number of species under a pro- 

 posed genus Gaurocrinus, which, like his Glyptocrinus, embraces 

 a heterogeneous assemblage of forms. It contains species of JReteo- 

 crinus, Glyptocrinus, and a new form with good generic characters, 

 in our opinion, for which we should be very glad to retain Miller's 

 name, if he had not expressly taken as its type Hall's Glyptocri- 

 nus O'Nealli, which is a typical Reteocrinus. We are, therefore, 

 obliged to adopt a new name, and propose Ptychocrinus, for the 

 reception of his Gaurocrinus splendens, and G. angularis, together 



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