89 



vided internally, and extends to the top of the arms where it 

 unites with a summit plate. The first regular interradial is of 

 moderate size, ten sided, and followed by two elongated plates in 

 the second range, and those by a long plate that is divided in- 

 ternally and extends to the top of the arms where it unites on either 

 side with a summit plate. The arms when closed are compact, 

 within furrows formed by the internal union of the long interbrachial 

 places. There are five plates at the summit that form a vault, 

 which is constricted above the tops of the arms, and bears a cen- 

 tral azygous orifice. This structure of the summit may be of 

 generic importance, and, if so, this species would belong to 

 Hypanihocrinus. We doubt the propriety, however, of founding 

 any genus of crinoids, on the structure of the vault or proboscis, 

 and, therefore, refer this species to Eucalyptocrinus. 



This species is distinguished by the pentagonal, funnel-shaped, 

 columnar cavity, broadly constricted calyx, fusiform arms, con- 

 stricted vault and elevation of the azygous orifice. 



Found by Mrs. J. M. Milligan, in whose honor we have pro- 

 posed the specific name, in the Niagara Group, in Decatur county, 

 Tennessee, and now in her collection, in Jacksonville, Illinois. 



ORDER BLASTOIDEA. 

 Family CODASTERIDiE. 



CODASTER JESSIEiE, n. sp. 



Plate V, Fig. 20, basal view; Fig. 21, side view; Fig. 22, summit. 



Calyx about one-fifth wider than high. Summit only moder- 

 ately convex. Transverse section of the basals subtriangular, with 

 concave sides. Transverse section above the basals subpentagonal. 

 Surface without ornamentation. 



Basals occupy nearly half the height of the calyx. They are 

 longitudinal, depressed at the sutures and rounded in the middle 

 part of each plate. The point for the attachment of the column 

 is exceedingly small. The two larger plates are of equal size and 

 pentagonal, the smaller one is tetragonal. Radials equal, wider 

 than long and the mesial gibbosity gives the pentagonal outline 

 to the summit. Part of the summit is destroyed in our specimen 

 12 



