1886.] NATURAL SCIENCES OP PHILADELPHIA. 201 



as the aral plates in Calceocrinu^, resting like them against the 

 hasals and supporting a sirailar anal tube. By thus changing 

 the respective parts into a relative position, the affinities wh'ch 

 exist between the two genera can be better appreciated. T.he 

 form of the calyx, however, the articulation between the basals 

 and radials, and the sloping position of the lateral rays is so 

 unique, and strikingly different from Catillocrinus and other 

 genera, that Calceocrinvs must be referred to a distinct family. 



The slight variations, which naturally occur in the branching 

 of the arms, were taken by Hall, and Meek and Wortlien, for 

 specific distinctions. We fear these differences are too trifling to 

 be regarded as such, and we have felt obliged to refer some of 

 their species to our list f synonj^ms. 



Postscriptum. While our descriptions upon the Calceocrinidse 

 were in press, we received a paper from Mr. E. 0. Ulrich (extracted 

 from the 14tli Ann. Rep. Geol. Surv. Minn., p. 104): Remarks 

 upon the names Cheirocrinus and Calceocrinus, with descriptions 

 of three new generic terms and one new species. The author sub- 

 divides the species heretofore known under Galceocrinioi into three 

 genera : Cremacrinus, Deltacrinus and ffah/siocrinus^ and applies 

 to them the family name "Cremacrinidse." There is, in our opinion, 

 no valid reason for discontinuing the names Calceocrinus and Calce- 

 ocrinidse. The genus Calceocrinus was properly defined by Hall 

 and others, and several species have been referred to it by them. 

 Moreover, Meek and Worthen's name Eucheirocrinusyvo\\\^ have 

 priority, and also Calceocrinidse, as both were proposed in 1873. 



Under Cremacrinus Ulrich placed the species in which the two 

 anterior radials (the two central plates of his) are connected ver- 

 tically ; under Deltacrinus those in which said plates are sepa- 

 rated by the two lateral radials (his two large dorso-lateral 

 pieces). This difference, we admit, exists between the Lower 

 Silurian and Subcarboniferous species, but in the Upper Silur 

 and Devonian the two forms pass gradually into one another, so as 

 to make a generic separation impracticable. Ulrich's statement 

 on p. 110, that Cremacrinus has " three primary radials," Delta- 

 crinus " five," Halysiocrinus " eleven," is based altogether upon 

 incorrect observation. All these species have but three arm- 

 bearing radials one of them compound and the plates which 

 Ulrich regarded as " eleven primary radials," are axillary bra- 

 chials of ascending orders. (May, 1886). 

 14 



