FOSSILS OF THE NIAGARA GROUP. 353 



GENUS EUCALYPTOCRINUS, Goldfuss. 



This genus has usually been described as having five basal plates ; but 

 Dr. Troost, in his Memoir on the Criuoidea, has described the genus as 

 having four basal or pelvic plates. 



In the study of the collections from Waldron, Indiana, in 1861-62, 

 this feature was fully ascertained, thus confirming the original observa- 

 tions of Dr. Troost.* 



The basal plates of the species of this genus are usually small, and 

 either concealed in the depression or covered by the column. 



The form and relations of these plates are shown in fig. 1, which 



represents the basal and first ^ig. 2. 



ra,dial plates of Uucal^ptocrinus PTV ^f 



ccelatus as seen from the in- ■^^"^^^ V^'' ^^ 



side, and showing more con- u^^ ^nN^ 

 spicuously than on the exte- J^yV /ff-v>c-' r^*i^~ 



rior. In the original specimen both these cy V^ r^^^^x^ WlT^ 

 and the lower part of the first radial plates /~^r^C/^^-?=n V /; 



are covered by the column. In the dia- ^7Yr=n ( ) r//"""] 

 gram, fig. 2, the basal plates of E. ccelatus ^'^ (![) )^r\^ 

 are given of the natural size, and in their ^ ^^^^\^ 



relation with the first radial plates ; the plates are shown from the exte- 

 rior, the ring indicating the extent of the column. 



This determination of the basal plates will remove the Genus Euua- 

 LYPTOCRmus from its present position among the Crinoidea which have 

 five basal plates, and bring it into association with Melocrinus. 



EUUALTPTOCRINUS CORNUTUS, N. S. 

 PLATE XI, PIGS. 8, 9, 10. 



Body (without the arms) somewhat turbinate, distinctly angular, with 

 the base broadly truncate and more or less concave. Basal plates 

 comparatively large, extending from the centre nearly one half the 

 distance to the edge of the truncation. First radial plates large, 

 forming the circumference of the base, and abruptly bending 

 upwards they extend nearly one-third the height of the calyx ; 

 second radial plates small ; third radials much larger than the 



* I did not at that time publish an account of this structure in my paper on the Waldron fossils, 

 wishing that it might first appear in the publication of Dr. Troost's Memoir; but since that has 

 been delayed, I notice it in this place, giving Dr. Tkoost the credit of the original discovery. 



