324 PROCEEDINGS OF THE ACADEMY OF [1885. 



STELIDIOCRINUS Angl., Rev. ii, p. 98. 



Additional species : — 



•1883. (?) Stelidiocrinus argutus (Walcott), Glyptocrinus argutus, 35th Rep. N. 

 York State Cab. Nat. Hist. (Adv. Sheet, p. 1), PI. 17, fig. 9.— Trenton 

 limest. Trenton Falls, N. Y. This is certainly not a Glyptocrinus. To 

 judge from the figure, it is closely allied to Stelidiocrinus, but may be the 

 type of a new genus. 



PATELLIOCRINUS Angl., Rev. ii, p. 100. 



MACROSTYLOCRINUS Hall, Rev. ii, p. 102. 



Additional species : — 



1882. Macrostylocr. fusibrachiatus Ringeberg, Journ. Cincin. Soc. Nat. Hist., vol. 



v, ]>. I !'.•, PI. 5, fig. 4. — Niagara gr. Lockport, N. Y. 

 1880. M. striatus, var. granulosus Hall, 28th Rep. N. Y. State Cab., p. 129; also 

 11th Geol. Rep. Ind., p. 258. — Niagara gr. AValdron, Ind. 



CENTROCRINTJS W. and Sp., Rev. ii, p. 104. 

 b. Melocrinites. 



GLYPTOCRINUS Hall, Rev. ii, p. 185. 



1883. S. A. Miller. Journ. Cincin. Soc. Nat. Hist., vol. vi (December). 

 1883. W. and Sp. Amer. Journ. Sci. (April), p. 255. 



1883. S. A. Miller. Ibid. (August), p. 105. 



Not Etheridge and Nicholson, 1880, Silur. Foss. of Girvan Distr., 



p. 328. 

 Syn. Pycnocrimis S. A. Miller. Journ. Cincin. Soc. Nat. Hist., vol. iv. 



Since the absence of underbasals is clearly proved, Glyptocrinus 

 differs from Mariacrinus only in the number-of basals, which is 

 five in place of four. Miller has founded the genus Pycnocrinus 

 upon a species which he had previously referred to Glyptocrinus. 

 Through the liberality of Mr. Miller, for which we are under 

 lasting obligations to him, we have been given the freest access 

 to his beautiful type specimens, with liberty to use them for our 

 descriptions. We are reluctantly compelled to say that in our 

 opinion Pycnocrinus is simply a young Glyptocrinus. The genus 

 was founded principally upon the absence of " secondary radials," 

 and the arms were said " to arise free from the primary radials." 

 This statement does not agree with our observations, as we find 

 in two of the specimens a minute interaxillary piece, and at least 

 one secondary radial. In the two others, which are even more 

 immature, the third primary radials, in part, take the functions of 



