the Morphology of the Blastoidea* 229 



obtained the specimen on which Conrad based the genus. 

 But he admits himself that its general form, which is all that 

 the^ figure shows, resembles that of Pent rem ites Nonvoodi, 

 which is a Granatocrimts, and of P. melo, which is a Schizo- 

 blastus. In fact it was not until the publication of Hall's 

 own observations in 1862 that the nature of Nucleocrinus was 

 satisfactorily known. Meanwhile, however, Homer * had 

 given an elaborate description of the P. (Olivamtes) Yemeni! i, 

 -Troost, and pointed out that it represented a new generic 

 type, for which he proposed the name of E/eacrinus. But 

 although it subsequently appeared that Eleacrinus Verneuili 

 and JSucIeocn'jiHs elegans are congeneric, Hall considered 



that there can be no doubt as to the propriety of restoring 

 the earliest name," i. e. Nucleocrinus. 



We entirely dissent from this proposition, and feel it only 

 right to adopt Bomer's name, as has been already done by 



C? 1 7 J_ • . 1 ,1 /> 1 1 • 1 ft t A . • . 1 11 



t 



Strictly adhering 



to the laws which govern naturalists in such cases, we cannot 

 m justice to Bonier set aside his name. The description of 

 Conrad was not only extremely imperfect, but it is entirely 

 erroneous and calculated to mislead the student in his efforts 

 to identify the fossil he attempted to describe. In a word, no 

 one could possibly recognize the genus from Conrad's descrip- 

 tion, since there is no section of the family Blastoidea pre- 

 senting such a structure." 



We have but little information to give respecting the 

 morphology of Eleacrinus, and are inclined to accept as correct 

 the analysis of the calyx of E. Verneuili as given by Bomer 

 with the modification introduced by Hall. Lyon's descrip- 

 tion % was much more elaborate than Bomer's, which he 

 spoke of as defective in many respects j but we have littie 

 doubt that in most points the one given by the German 

 palaeontologist is the more accurate of the two. Lyon's 

 analysis of the interradii was not accepted by Hall, who fol- 

 lowed Bomer in considering the four normal ones as formed 

 merely by the large deltoid (oral) plates. On the anal side, 

 however, Hall admits a triple division of the interradius, 

 though not in the manner described by Lyon, but as fol- 

 lows : — " A narrow intercalated plate on the anal side reaches 

 from the aperture to the radial plate dividing the interradial 

 on that side into two narrow curving plates." 



Monographic der Blastoideen (Berlin, 1852), pp. 55-60, Taf. v. fig. 1. 

 t "Catalogue of the Palaeozoic Fossils of North America. — Part 1. 

 Pal. Echinodeinmta/' Tra , St. Louis Acad. I860, vol. ii. no. 2, p. 3(5S 

 (note). 



^ Rep. Geol. Surv. Kentucky, vol. iii. p. 487, 



