84 



FAMILY RHODOCBINIDiE. 



GONIASTEROIDOCRINUS FABERI, n. Bp. 



Plate V, Fig. 2, basal view; Fig. 3, side view. 



Species large. Calyx subcylindrical to near the summit where 

 it curves outward. No radial ridges. Basal plates depressed. The 

 other plates tumid, nodose or spinous. Our specimen is a cavity 

 in a rock, preserving all the external features of the calyx, except 

 the sutures between the basal plates, and by taking an impres- 

 sion from it the artist has been able to furnish a basal and side 

 view. 



The basal plates form a regular pentagon one-half wider than 

 the diameter of the column. The columu is round. Subradials 

 large, almost regularly hexagonal, and each one bears a long, 

 sharp, conical spine, that is directed downward, at an angle of 

 about forty-five degrees. The calyx will rest upon the points of 

 these spines. First radials a little smaller than the subradials, 

 wider than long, heptagonal, and each one bears a long, sharp, 

 conical spine that is directed horizontally. Second radials about 

 one-fifth as large as the first, convex, quadrangular and longer 

 than wide. Third radials about twice as large as the second, 

 tumid, octagonal, and support on each superior lateral side two 

 secondary radials. The superior face is truncated by an inter- 

 secondary plate that is followed by two plates in the second range. 

 The calyx curves out rapidly, from the third primary radials, and 

 the secondary radials spread, so that at the summit of the second 

 secondary radials, they are directed laterally at an angle of about 

 forty-five degrees. Beyond this point our specimen is not pre- 

 served. These plates are subnodose. 



There are ten plates shown in an interradial area in our speci- 

 men, and we suppose that to be the limit. The first plate is 

 almost in line with the first primary radials and about two-thirds 

 as large, hexagonal, and bears a long, sharp, conical spine that is 

 directed horizontally. It is followed by three smaller, subequal 

 plates in the second range, each one of which bears a large cen- 

 tral node; and these are followed by three still smaller plates 

 in the third range, each one of which bears a central node. Above 

 these there are three plates shown in our specimen, each one of 

 which bears a small central node. 



