29 



radials and first iuterradials, it resembles G. dccnddclijliis, but is 

 quite different iu all other parts, beside having only ten aims. It 

 can uot be mistaken for any other described species. 



Found in the Trenton Groui), iu Mercer county, Kentucky, and 

 uow in the collection of Wm. F. E. Gurley. 



F.\MiLY CALCEOCKINID.E. 



CALCEOCllINUS KENTUCKIENSIS, U. sp. 



Fluff If, Fig. 2Jf, (Ulterior side rlew; Fig. 'Jo, posterior side. 



.showing place of nttdehrnerit of the eolunm of 



so Die specimen . 



From the cicatrix for the attachment of the column, we infer, 

 that the body hung close to the column; the column is small and 

 round. AA^e have two specimens, about equally well preserved, 

 both are silicified, but show the sutures correctly, unless it may 

 be in the basal plate. The basal plate is triangular and, as shown 

 by the sutures, composed of four anchylosed plates, though the 

 sutures are obscure. The columnar facet is at the posterior angle. 

 There is a wide gaping suture between the basals and the radials 

 on the anterior side, that is somewhat denticulated ou the anterior 

 margin. Following this gaping suture on the anterior side there 

 are three radials, in the first transverse series; the middle one is 

 twice as long as wide, quadrangular, and constricted iu the mitl- 

 dle; the outer ones are hexagonal, about twice as wide and aV)out 

 twice as large as the middle one. The second transverse series 

 commences in the middle part with a short wide jjlate that rests 

 upon the superior side of the middle plate in the first series, and 

 upou the iuuer sloping sides of the two lateral j^lates, in the first 

 series. It is about three times as wide as long and is succeeded 

 by a plate, that contracts rapiiUy upward, somevrhat in the form 

 of the frustum of a cone. It has a length about equal to th(? 

 shorter width. This last, plate bears a free siugle arm composed 

 of rather long round joints. Tlie superior lateral side of each of 

 the lateral plates iu the first series bears two brachial plates, the 

 second one of which is axillary and bears free arms. Evei'y s<'C- 

 ond or third plate in the free arms is axillary, though one of the 

 rays thrown off from each axillary plate is smaller than the main 

 arm and does uot bifurcate again. 



