458 



REMARKS ON NEW SPECIES OF CRINOIDEA, 



that species these pieces are about three times as long as their thickness; in our species 

 their length is about equal to their diameter. 



POTEPJOCEJNUS. Miller, 1821. 



{Nat. Hist. Crinoidea.) 



POTERIOCRINUS SIMr-LEX, n. s. 



PI. XXVI, Pig. f. 



Body conical, long and slim ; basal pieces long and thin ; subradials and two of the 

 radials nearly of equal length ; the pieces gradually increasing in width as they rise in the 

 calyx. In our specimen the anal side is presented ; it consists of about five pieces ; the 

 first is nearly as large as the first radials, and supports two long pieces a little smaller; all 

 the pieces are slightly gibbous ; sutures at the junction of the pieces strongly marked by 

 the depression formed by the sides of the plates. The pieces are very thick ; cavity of the 

 body small; arms and summit unknown; column round, rapidly tapering from the body 

 downward, formed of circular disks of equal thickness. The surface of our specimen is 

 smooth, showing no markings. 



Size of Specimen. 



INCHES. 



Length of calyx to top of second radials, ...... .32 



Diameter at summit of second radials, 22 



Diameter of base at top of column, ....... .15 



Locality and Geological Position. — Nucleocrinus or lower crinoid bod, near mill, on the Palls of the 

 Ohio. 



This species is longer and thinner than any species observed ; approaches P. rhenanus, F. 

 A. Boomer, nearer than any other, and the form, the number, and arrangement of the 

 pieces in the anal field. 



POTERIOCRINUS CYLINDRICtJS, 71. ,S. 



PI. XXVII, Pigs. 1, 11. 



Body, from base. to the free rays, cylindrical; abruptly rounded on the basal pieces; 

 basal pieces short and thick, forming a low broad cup ; radial pieces short ; two of them, 

 that are complete, reach the second radial; this is also quite short, and appears to bear a 

 third radial, also short ; it reaches to the base of the free rays ; arms unknown. The dome, 

 or proboscis, in our specimen, is crushed ; its form is not known ; the loose, disarranged 



