HEXACRINID^. 737 



Horison and Locality. — Upper part of St. Louis limestone ; Grayson, 

 Edmondson, and Pulaski Cos., Ky. 



RenuirJcs. — The type specimen, which is figured on Plate LXXVIII., 

 Fig. 6, is in the Lyon collection ; that of Figs. 4a, h on the same plate is in 

 the collection of Wachsmuth and Springer. 



Dichocrinus elegans Cass, and Lyon, in our opinion, belongs to this species. 

 The type specimen, which is badly crushed, is possibly a little more lobed at 

 the ventral disk, but that alone is not sufficient to make it a different species. 

 The differences to which the authors refer are not borne out by the facts. 

 Talarocrmus sijmmetricus, like T. elegans, has four arms to the ray, and not 

 two, as stated in the description. 



Talarocrinus ovatus Worthed. 

 PMe LXXVIII. Figs. 2a, b. 



1882. Worthen; Bulletin I., Illmois State Mus. Nat. Hist., p. 36. 



1883. WoETHEN ; Geol. Rep. Illinois, Vol. VII., p. 31i, Plate 29, Kg. 11. 

 1885. W. and Sp. ; Revision Palaiocr., Part III., p. 120. 



Calyx more elongate than in the preceding species, ovate in its general 

 outline, the dorsal cup proportionately higher and less spreading, the radials 

 more evenly convex, and not tumid at the upper end. Basal cup compara- 

 tively large and deep, truncate at the bottom, and slightly excavated for the 

 reception of the column ; the sides but little expanding. Eadials somewhat 

 longer than wide, a little wider above than below, slightly inflected at the 

 upper end; their lower faces straight, except at the anterior plate where 

 they are distinctly angular ; the upper deeply excavated to about one half 

 their width, and the facet directed obliquely outward. Anal plate lono-er 

 than the radials and heptagonal. The costals rest obliquely upon the radials 

 and are larger than usual in this genus, forming a small triangle with con- 

 cave sides. Of the disticlials only one row of plates is visible, which are 

 short and excavated at the upper face. This may have been followed 

 by an axillary distichal, or have directly supported the arms. The number 

 and structure of the arms unknown. Ventral disk highly elevated the 

 interambulacral spaces depressed, especially near the arm bases. Anal area 

 projecting, giving to the ventral di.sk, as seen from the summit, a distinctly 

 hexagonal outline. Interradial plates three and one; the middle plate of 

 the first range, and the upper, very large, the two at the sides small, about 

 half as long as the middle one and considerably narrower. Anal area elon- 



