246 Cincinnati Society of Natural History. 



species of this genns the raj's are uniform in this respect, it is prob- 

 able that such is the case here. 



Interradials — These are hexagonal, and so arranged that in all the 

 areas except that on the az3'gos side there is first one plate, then two 

 above this for two or three ranges, after which the plates become 

 smaller, and their arrangement too indefinite to be determined in the 

 specimens studied. The azj'gos side has first one plate, above this 

 two in the first range, and three in a few succeeding ranges, when the 

 plates become smaller and the arrangement is not clearly shown. 



Inter axillaries — These are numerous, hexagonal or pentagonal, and 

 slightly elevated in the center, forming blunt spines or tubercles. 

 Before the arms become free, at the top of the bod}-, they send off" a 

 number of jointed processes like large pinnulae, which are grooved up- 

 on the inner side, but soldered together by small plates. 



Body — These plates, together with the radial frame work, and the 

 interradial and interaxillary areas, make up the bod}^ of the crinoid, 

 which is plainly pentagonal in outline, being rendered so by the con- 

 spicuous ridges formed by the elevated central portion of the radials, 

 and the greater depression of the interradial and interaxillary areas. 



The Column — This is round, and much resembles that of the G. de- 

 cadactylus. Several inches of the column attached to one of the spe- 

 cimens, show that the plates become slightly thinner as they approach 

 the bod3^ 



Arms — Thirt}^ (30?), composed of nearly equal, slightly cuneiform 

 plates; they are long, taper very gradually, and with the much elon- 

 gated, slender piniTulne, give the species a peculiai'ly graceful appear- 

 ance. 



The Pinnitlce — These are long, slender, ten or twelve jointed, and 

 arise from the inner thickened extremities of alternate plates upon 

 either side of the arms. 



The Vault — The mere fragment of the vault preserved shows that 

 it is composed of small irregularly pentagonal or hexagonal pieces. 



Remarks — This rare and beautiful crinoid is named in honor of its 

 discoverer, Mr. J. M. Richardson, of Wilmington, Clinton Co., Ohio, 

 who found it in the upper part of the Cincinnati Group at that place. 

 The specimens figured belong to the collection of Dr. L, B. Welch, of 

 Wilmington. These very earnest naturalists have devoted much time 

 to the collection and study of the rare fossils in the region about 

 Wilmington, and have added largely to our knowledge of its pali\?on- 

 tological treasures. 



It seems proper, in concluding this description, to make some re- 



