44 Trans. Acad. Sci. of St. Louis. 



Pentremites grosvenori, Shuraard. 



Troostocrinus grosvenori, Etherid.»e and Carpenter. 



Troostocrinus nitidulus, S. A. Miller and Gurley. 



Metablastus varsouviensis , Etheridge and Carpenter. 



Pentremites varsouviensis, Meek and Worthen. 



Metablastus wachsmuthi, Gurley. 



Troostocrinus wachsmuthi, Gurley. 



6. Saccoblastus meekianus, K. Etheridge fil. and Carpenter. 



Warsaw limestone. 

 Tricoelocrinus meekianus, Eth. and Carp. 



4. Genus Clavaeblastus. 



General form of the body club-shaped, or elliptical. Am- 

 bulacra narrow and linear. Deltoids not visible externally, 

 except on the posterior side, where the deltoid piece supports 

 the anal opening which lies outside of the genital openings, 

 which are confluent and surround the central opening. Col- 

 umn round. Upper Silurian and Devonian. If more 

 material should be collected from the Devonian rocks, it 

 may bring to light characteristics as yet unknown, which may 

 necessitate the creation of a new genus for this form. 



This genus will include the following species : — 



1. Clavaeblastus Americana, W. H. Barris. Hamilton 



group. 



Pentremitidea americana, W. H. Barris. 



2. Clavaeblastus filosa, I. F. Whiteaves. Hamilton group. 



Pentremitidea filosa, I. F. Whiteaves. 

 Pentremites whitei, Hal!. 



3. Clavaeblastus milwaukensis , S. Weller. Hamilton 



group. 

 Pentremitidea milwaukensis, S. Weller. 



4. Clavaeblastus REiNWARDTii, G. Troost. Niagara group. 



Pentremites reinwardtii, Troost. 

 Troostocrinus reinivardtii, Shumard. 

 Pentremites subcylindi'icus , Hall and Whitfield. 



