FOSSILS OF THE NIAGARA GROUP. 36 § 



EUCALYPTOORINUS CRASSUS, HaLL. 



PLATE XI, FIGS. 2, 3. 



Eucalyplocrinus crassus, Hall ; in Transactions of the Albany Institute, IV, p. 197. 1862. 



Specimens which are casts of the interior and impressions of the 

 exterior, present the general aspect of this species. It is extremely 

 variable in form. Sometimes it is regularly turbinate and convex on 

 the sides; other specimens are extremely elongate and sometimes 

 abnormal in their development, having the supraradial plates united at 

 their lateral margins, and the second interradials with the first axillary 

 plate resting upon their upper sloping sides, instead of the truncated 

 upper face of the interradial and third radial plates. This variation 

 sometimes extends only to one or two of the rays, and sometimes, as 

 far as can be seen, to all the plates of these series. 



Formation and Localitij. — In hmestone of the Niagara group at Racine, 

 Wisconsin. 



EUCALYPTOCRINUS OBCONICUS, N. S. 

 PLATE XI, FIG. 1. 



Body small, reversed conical ; base narrowly rounded or obtusely pointed ; 

 basal plates small and curving upwards. First radial plates com- 

 paratively large ; the second and third smaller. The two supraradial 

 plates join at the lateral margins, and the narrow interbrachial rests 

 upon them, and does not truncate the third radial. First interradial 

 plate large, narrowly truncate above. 



This species occurring in several specimens is a remarkable form of 

 EucALTPTocRiNUS, being much more slender than any other species of the 

 genus known to me ; and presenting the peculiar relations of the inter- 

 brachial plates, which are elevated to a higher position than they occupy 

 in the normal structure of the genus. 



The position of the interbrachial plates, which appear to be uniform 

 in this species, is sometimes observed in specimens of E. crassus. 



Formation and Locality. — In limestone of the Niagara group at Racine, 

 Wisconsin. 



