56 [Assembly 



FORBESIOCRINUS LOBATUS, var. TARDUS. 



A "well-preserved specimen of this Crinoid shows no important or essential dif- 

 ference from F. lohatus of the Hamilton group of New-York, described in the Fif- 

 teenth Report on the State Cabinet, page 124. The divisions and subdivisions of the 

 rays are of precisely the same character, and in the same order. The rays are sub- 

 angular, and the third radial plate is more prominent than other parts of the ray; 

 though, from its weathered condition, not so prominent as those of the Hamilton 

 species. 



In the specimen under consideration, the plates of the ray are not quite so deeply 

 depressed in the middle as the original of F. lohatus; but this difference may be in 

 part due to the greater pressure which this one has undergone. 



The difference in geological position is greater than I know in any other example 

 of a species of this family, for the Hamilton species is from the shales of the higher 

 portion of that group. 



FORBESIOCRINUS KELLOGI ( n. s.). 



Body and arms somewhat robust ; body short. Basal plates barely 

 visible above the column : subradial plates small and triangu- 

 lar. The primary radial series consists of four plates in each 

 ray, which diminish from beloAV upwards. The secondary radial 

 series consists of five in each division between the first and 

 second bifurcations, while there are from six to eight plates in 

 each division between the second and third bifurcations The 

 antero-lateral interradial areas have one somewhat prominent 

 plate of medium size, which rests upon two adjacent first ra- 

 dials, and lies between the second radial plates. The postero- 

 lateral interradial spaces have a single smaller plate, situated 

 as in the other spaces. The first anal plate is about as large as 

 the larger interradial plate : no other plates have been deter- 

 mined above this one. 



The branches of the ray divide twice above the first bifurcation, 

 and each bifurcating plate is strongly nodiform, the node angu- 

 lar and transverse. The surface of the ray, to the first division, 

 is regularly convex, and the divisions become successively more 

 angular upon the back. The surface of the plates is striato- 

 granulose. 



Column strong, composed near the body of very thin plates, and 

 rapidly tapering below. 



In the structure of the body, this species is most nearly allied to F. communis; 

 differing in the nodose bifurcating plates, and in the angular divisions of the ray. 



GENUS POTERIOCRINUS ( Miller). 



POTERIOCRINUS CRINEUS ( n.s.). 



Body turbinate, of medium size. Basal plates short : subradial 

 plates of moderate size. First radials wider than high ; second 

 radials shorter than the first, strongly wedgeform above, sup- 

 porting an arm on each upper side. 



Arms dividing on the tenth or twelfth plate from their origin ; 

 above which, they are simple as far as known. 



