GENUS MACROSTYLOCRINUS. 327 



of parts corresponding with the Waldron specimens. Most of these are 

 small, scarcely exceeding an inch in height, but a single specimen from 

 Wa,ukesha is nearly three inches in length ; and a fragment of another 

 from Racine indicates an individual of still larger dimensions. The casts of 

 the smaller specimens have the arm bases more prominent than is usual in 

 the Indiana specimens. 



Formation and locality. The original specimens are from a calcareous 

 shale of the Niagara group at Waldron, Indiana. It occurs in the limestone 

 (Niagara group) at Racine and Waukesha, Wisconsin. 



GENUS MACROSTYLOCRINUS* (Hall). 



CYTOCRINUSt (Roemer). 

 MACROSTYLOCRINUS STRIATUS. 



Macrostylocrinus striaius : Hall, Transactions Albany Institute, Vol. v. 1863. 



The originals of this species are from Waldron, Indiana. A cast of a 

 species of this genus from Racine is similar in form and proportions, and 

 is probably identical with that one. 



GENUS MELOCRINUS (Goldfuss). 



MELOCRINUS VERNEUILI. 



Adinocrinus verneuili : Troost, Catalogue of Crinoidea. Proceedings of the Ameri- 

 can Association for the Advancement of Science, p. 60. 1849. 



Turhinocrinites verneuili : Troost, MS. 



Not Actinocrinus verneuilianus : Shumard, Geol. Rep. of Missouri, pa. 193, pi. A,f.l. 



• Body turbinate, strongly lobed at the arm-bases. Basal plates four ; suc- 

 ceeded by five radial series of three plates each, and subdividing upon 

 the last one. Interradial series composed of one, two, and three plates 

 in the successive ranges. Anal area scarcely differing from the other 

 interradial spaces. 

 This species has the structure of Melocri7ius, and though differing in 



form from the typical species of the genus, I see no sufficient reason for 



separating it at the present time. 



Formation and locality. In limestone of the age of the Niagara group 



at Racine, Wisconsin. Dr. Troost's specimens are from Decatur county, 



Tennessee. 



* Palaeontology of New-York, Vol. ii. 1852. 



t Silurische Fauna des Westlichen Tennessee 1860. 



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