50 Trans. Acad. Sci. of St. Louis. 



3. Olivanites elegans, T. a. Conrad. Devonian. 

 JSTucleocrinus canadensis, H. Montgomery. 

 mideocrinns hallii, L. Vanuxem. 

 Elaeacrinus elegans, Shumard. 

 Nucleocrinus venustus. Miller and Gurley. 



*4. Olivanites geeeni, S. A., Miller and W. F. E. Gurley. 



Devonian. 



JSlucleocrinus greeni, Miller and Gurley. 



*5. Olivanites globosus, Troost. Devonian. 



6. Olivanites lucina, Hall. Devonian. 



Nucleocrinus lucina, Hall. 



*7. Olivanites meloniformis , W. H. Barris. Devonian. 



Elaeacrinus meloniformis, Barris. 



8. Olivanites obovatus, W. H. Barris. Devonian. 



Elaeacrinus obovatus, Batri?;. 



9. Olivanites verneuili, Lyon. Devonian. 

 Pentremites verneuili, Troost. 



Elaeacrinus verneuili, Roemer. 

 Nucleocrinus verneuili, Bather. 



Those marked with an asterisk may have to be placed 

 in another genus or may prove to be identical with one or 

 another already known species, which facts can only be 

 estabhshed when more material for comparison is available. 



2. Family Eleuthekoblastidae. 

 1. Genus Eleutheroblastus. 



General form elliptical, truncated at the summit and sub- 

 triansular at the base. Base very irregular, subtriangular at 

 the lower part, and prolonged on one of its sides to a remark- 

 able length. It consists of three pieces, one small rhombic 

 piece and two large pieces prolonged nearly to the middle of 

 the calyx. Fork pieces four, non-symmetrical, each having a 

 lono- sinus in the center for the reception of the ambulacrum. 

 The two middle pieces have a shorter sinus, whereas the two 



