25 



Family CYATHOCKINID^. 



CARABOCRINUS OVALIS, n., Sp. 



Plate II, Fig. 20, azygows side view; Fig. 11, opposite view. 



Our specimens are silicified and part of the plates in the arms 

 do not show the sutures. Calyx snboval in outline, the smaller 

 end below, which is narrowly rounded, and the scar for the at- 

 tachment of the column xery small. Surface destroyed in silici- 

 fication. Basal plates small. Subi-adials the largest plates in the 

 calyx, wider than high and evenly rounded. The radials are the 

 next in size, very evenly rounded and slightly truncated about 

 one-third the width in the superior central part for the free arms. 

 The arms are small and round and bifurcate on the second plate. 

 They bifurcate again on the third or fourth plate, the silicifica- 

 tion destroying the sutures. And one of the arms in every ray 

 bifurcates again, making thirty arms in this species. The arms 

 cluster together over the vault and are so interlaced that more 

 divisions of the arms may take place which are not disclosed by 

 either of the two specimens before us. The azygous plates are 

 arranged as in Carabocrinus radiatus, but the first plate which 

 truncates a basal plate is regularly hexagonal and about as 

 wide as high, and thus differs in form from C. radiatus. The 

 second plate is smaller and truncates a subradial. The third 

 plate is fully as large as the first and longer than wide. 



The general outline of the calyx in this species is much like 

 Carabocrinus rancor llandti, but the arms are quite different, as 

 the first bifurcation, in that species, takes place on the third 

 plate, while in this one, it takes place on the second plate. The 

 general form of the calyx is altogether different from that in 

 C. radiatus, but the first bifurcation takes place on the second 

 plate in the free arms, in both species, though above that the 

 arms are altogether different. 



Found in the Trenton Group, in Mercer County, Kentucky, and 

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



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