212 Twenty-fourth Report on the State Museum, 



* Heteroceinus juvenis n. sp. 



Plate 5, figs. 9, 10. 



Body minute, the greatest diameter of the cup not exceeding a 

 line, and the height from the base to the top of the first arm plates a 

 line and a half. 



Basal plates appearing only as triangular points at the lower lateral 

 angles of the adjacent subradials. Subradial plates wider than high, 

 hexagonal. Three of the first radial plates higher than wide, each 

 supporting a single smaller arm plate, which presents the appearance 

 of having had another plate above ; the other two radial plates are 

 short, quadrangular ; one of them supporting a small plate above, and 

 the other one a wedge-form plate, upon which rest two other small 

 plates, one larger than the other ; the largest of these has the position 

 and appearance of an anal plate. 



Surface of plates smooth. 



Column distinctly pentangular, nearly as large as the diameter of 

 calyx, composed of alternating thick and thin plates. 



This crinoid may be only the young of some previously described 

 species ; but as there have been several individuals found, all pre- 

 senting the same characters and of about the same size, I have 

 thought proper to designate it as a distinct species for the present. 



Formation and locality. In shales of the Hudson-river group, 

 at Lebanon, Ohio. From Mr. J. Kelly O'JSTeall. 



HeT^EEOCRINUS ? (loCEINUS) POLYXO U, S^, 



Plate 5, figs. 1-4. 



Calyx short, broadly turbinate and strongly pentalobate, consist- 

 ing of only two ranges of visible plates. 



Basal plates undeveloped and entirely concealed by the column ; 

 sometimes seen on its removal in large individuals. Subradial plates 

 very short, their lateral margins reaching but Jittle above the base, 

 strongly wedge-form above. Radial plates wider than high ; nearly 

 the entire width of the upper margin occupied by the cicatrix for the 

 attachment of the arm. I^o anal plates have yet been observed in 

 any of the individuals examined. 



Arms long and slender, with frequent bifurcations ; composed in 

 the lower part of short plates, the upper margins of which project 

 beyond the base of the next succeeding plate ; in the upper part, the 

 arms are proportionally narrower and somewhat carinate on the back. 

 The first division of the arms takes place on the second radial plate 

 in one ray, on the sixth plate in another, and in the other three rays 



