DESCRIPTIONS OF THE SPECIES. 213 



in 1881 ; while in 1883 we gave our reasons ] for adopting Roemer'a name Eloea- 

 crinus with the modified analysis of the calyx as suggested by Hall, and the same 



course was taken by Harris - soon afterwards. 



Remarks. It appears to us that there can be no question as to the justice of 

 employing Roemer's name for this generic type in preference to that proposed by 

 Conrad, who regarded the basal concavity as a single " perforation at top." It was 

 by this character onlj that he distinguished Xttcleocri/ius from I'cvtrcuiites, which 

 has five summit-openings round the central mouth. Itoemer gave a full description 

 of Elceacrinus in 1851, and it was not until the publication of Hall's observations 

 in 1862 that the nature of Nueleocrinus, as typified by N. elegans, Conrad, was 

 satisfactorily known 3 . But although it subsequently appeared that Elceacrinus 

 Vemeuili and Nueleocrinus elegans are congeneric, Hall considered "that there can 

 be no doubt as to the propriety of i-estoring the earliest name," i. e. Nueleocrinus. 



\Ye entirely dissent from this proposition, and feel it only right to adopt Uoemer's 

 name, as has been already done by Shumard 4 , with the following remarks: — 

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

 justice to Roemer 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 description, since there is no 

 section of the family Blastoidea presenting such a structure." 



We are inclined to accept as correct the analysis of the calyx of E. Verm uili as 

 given by Roemer, with the modification introduced by Hall. But in other respects 

 we have little doubt that the one given by the German Palaeontologist is the most 

 generally accurate of any which have hitherto appeared. Lyon believed himself to 

 have discovered that below the pieces which Roemer described as basals there are 

 three yet smaller ones, separating them from the top stem-joint, and also inter- 

 radial in position. In accordance with his peculiar system of nomenclature, he 

 transferred the name " basals " to these plates, and called the basals of Roemer 

 " primary radials," although they are only three in number and are not situated in 

 the direction of the rays (PI. II. fig. 45) ; while the fork-pieces or true radials were 

 called by him " primary radials, second series." Lyon's description was accepted by 

 Billings, who corrected the errors in his terminology, and pointed out that the six 

 plates described by Lyon as basals and as primary radials together correspond " to 

 the six pieces which constitute the compound basal plates of Pentremites." But 



1 Ann. & Mag. Nat. Hist. 1 883, vol. xi. p. 229. 2 Report Geol. Survey Illinois, 18S3, vol. vii. p. 357. 



3 In a paper which was published in the following year (1863), Shumard said, " It is possible that the 

 genus Nueleocrinus, proposed by Conrad in 1842, may be identical with Elceacrinus; but the meagre and 

 unsatisfactory description of Conrad does not apply to any of the forms we propose to group in Elceacrinus." 

 (^Trans. St. Louis Acad. Sri. L863, vl. ii. no. 1, p. 112.) 



4 Trans. St. Louis Acad. Si i. 1865, vol. ii. ii". 2. p. 368, note. 



