REVISION OF PALEOZOIC STELLEEOIDEA. 81 



Abactinal area unknown, but probably that of Mesopalseaster and 

 nearest to M. shafferi. 



Formation and locality. The holotype was found by Faber in the 

 Maysville formation at Cincinnati, Ohio, about 350 feet above the 

 Ohio River. The type is in the University of Chicago Museum 

 (No. 9575). 



Remarks. This interesting species need be compared only with M. 

 shafferi. It differs in having the axillaries in the axils of the rays 

 and not inside the basal inframarginals as in the latter form. Then 

 in M. shafferi the inframarginals are actinal in position throughout, 

 while in M. intermedius they are more on the sides. Further, in the 

 new form the ambulacral furrows are well developed with large 

 ambulacralia, while in M. shafferi the furrows are narrow and the 

 ossicles rarely seen. 



MESOPAL^SASTER FINEI (Ulrich). 

 Plate 7, fig. 5; plate 9, fig. 5. 



Palseaster finei ULRICH, Journ. Cincinnati Soc. Nat. Hist., vol. 2, 1879, p. 19, pi. 

 7, figs. 15-156. 



Original description. "Small; rays five, of medium length, rather 

 broad, pointed and narrower where they are attached to the much 

 contracted body [probably due to distortion], than they are about 

 the center of their length. 



" Dorsal side of rays composed of four [about seven, the supra- and 

 inframarginals, radials, and two intercalary columns] rows of pieces, 

 that are quite close [?] fitting, as wide as long, from 12 to 14 in each 

 row, and increase in size inward to the disk, which is composed of 

 irregularly shaped and prominent pieces some of which are smaller 

 and others larger than those composing the rays; the pieces in the 

 marginal rows [four columns infra- and supramarginals] are more 

 prominent than the two [there are three, radials and two intercalary] 

 rows between them, and have a small pit in the center, probably for 

 the articulation of a spine [all of the plates originally bore several 

 short slender spines]. Madreporiform body rather small, circular, 

 very prominent, and marked by strong striae, which become more 

 numerous toward the margin by intercalation. 



"Marginal [inframarginal] pieces on the ventral surface, convex, 

 quite as long as wide, and numbering in different specimens on each 

 side from 11 to 12 [probably not more than 8 or 9]; the piece at the 

 junction of the rays is three times as large as any other of the series, 

 subcircular and very convex. [It appears that this large plate is an 

 axillary interbrachial since upon it proximally rest two basal plates 

 of the inframarginal series.] 



