282 S. WELLER FAUNA OF THE FERN GLEN FORMATION 



costal plate is axillary and extends horizontally from the calyx, with a 

 distinct constriction at its proximal extremity, dorsally and laterally. 

 The surface of the dorsal cup is marked with rounded tubercles; on the 

 base they are arranged in a circle of ten around the stem facet, with 

 usually an additional one or two in each distal angle of the disk; each 

 radial plate carries five or six similar tubercles. Height of the ventral 

 disk nearly equal to the dorsal cup. The first interradial plates between 

 the arm bases are nearly vertical in position, eight-sided, and with two 

 other plates, supported laterally and ventrally, occupy the entire space 

 between the bases of the rays ; in all except the posterior side, these plates 

 are flat, but posteriorly the central plate bears a low, rounded, central 

 node. Above the base of the rays the ventral plates are nearly uniform 

 in size, slightly convex or obscurely nodose, and generally hexagonal in 

 form, with a few usually inconspicuous smaller and less regular plates 

 which are mostly situated just above the arm bases. The anal opening 

 is eccentric and is directed ventrally. 



The dimensions of the type specimen are : Height of calyx, 7 milli- 

 meters ; width at top of radial plates, 9 millimeters. 



Remarks. — In its tuberculate basal and radial plates this little crinoid 

 resembles several species of Platycrinus from the Lower Burlington lime- 

 stone, but it is clearly distinct from any of them. From the Kinderhook 

 faunas no species with such distinctly tuberculate plates have been pre- 

 viously described. 



The specific name has been given in honor of Mr Frank Springer, 

 whose great familiarity with American crinoids has been most generously 

 placed at the disposal of the writer in the identification of many of the 

 obscure crinoidal fragments which occur so abundantly in the Fern Glen 

 collections. 



RHODOCRINUS PVNCTATUS n. sp. 



Plate 11, figures 15-16 



Description. — Calyx small, subglobular, contracted to the arm bases, 

 with a deeply indented base. The plates marked by minute, closely 

 arranged pits or punctaa, which can only be seen with a magnifying glass. 

 TJnderbasals minute, included within the excavated base and covered by 

 the column. Basal plates the largest plates of the calyx, their proximal 

 portions abruptly incurved to form the sides of the basal excavation. 

 Eadial plates heptagonal; first costals very small, quadrangular; second 

 costals axillary, pentagonal or hexagonal in form, as large or slightly 

 larger than the first costals ; distichals one in each series, their distal mar- 

 gins notched by the arm openings. First interbrachials a little smaller 



