454 



REMARKS ON NEW SPECIES OF CRFNOIDEA, 



basal pieces are remarkable for tbe perfectly level inferior surface, except at tbe points, 

 wbich are slightly elevated. The first radials are very large, each bearing near its centre 

 a stout spine, nearly half an inch in length, which is pointed outward and upward. Three 

 of the radials are hexagonal, two subseptagonal — differing slightly in size. Each bears 

 a second radial, of variable size and form : two are pentangular ; three subquadrangular ; 

 some arc plane-surfaced, others are slightly convex. The third radials are very small; 

 differing in size ; pentangular ; some of them arc so short as to appear triangular ; these are 

 about five times as wide as high ; they support one or two circular or crescent-shaped 

 pieces ; these, the bases of the free arms, ten in number. Their form and arrangement arc 

 unknown. 



From the notch between the sides of the first radial pieces, rise five intcrradials of the 

 first scries, variable in size and form ; the largest are hexagonal, the others subquadrangu- 

 lar; they each support two intcrradials of the second series; different in form and size; 

 small. The third scries of interradials are very small; one or two to each field; their 

 upper extremity extending upward between the groups of arm-bases. The arm-bases of 

 each group are quite close to each other, but they appear to have a slim, long piece be- 

 tween them. 



The covering of the dome is absent; its form, and the arrangement and character of the 

 pieces covering it, are unknown. 



This species, as seen in our example of it, docs not show any surface-marking on the 

 plates; they have, no doubt, been lost from our specimen by the loss of the integument 

 which covered their surface. 



Size of Specimen. 



INCHES. 



Height to free arms, .......... .60 



Diameter at free arms, ......... .70 



Diameter to end of spines on first radials, ...... 1.50 



Diameter of united basal pieces, 40 



Diameter of first radials, ......... .35 



Locality. — Nucleocrinus or lower crinoid bed, Falls of the Ohio; very rare as good specimens ; 

 plates and fragments not rare. 



This species has many of the characters of Dolatocrinus. It is not nearly related to any 

 known species of Actinocrinus, except A. muliicornus, described in this paper. It will be 

 readily distinguished from all Actinocrinus, by the spines, which rise so prominently from 

 the first radial pieces. 



