BRADLEY: BRACHIOPODA OF THE MAQUOKETA OF IOWA. 517 



R. altidorsafa. They are much smaller than R. kingi and show the 

 tendency to dwarfing that characterizes this fauna. R. subquadrala 

 and jR. altidorsata dift'er greatly from R. kingi and seem to be the first 

 dwarf forms described from the Maquoketa. 



Locality: — Lower Maquoketa at Clermont, Iowa. Holotype, 

 M. C. Z., 8,544. 



Rafinesquina subquadrata, sp. nov. 

 Plate 2, fig. 1. 



Shell of medium size, with a tendency to squareness; width at 

 hinge-line usually maintained and occasionally slightly exceeded as 

 far as two thirds the distance to the anterior margin. Cardinal angles 

 regularly square, but in some specimens slightly alate. 



Striations of the pedicle-valve alternate; usually three, sometimes 

 two or four finer striae embraced by two coarser ones in the region 

 directly anterior to the beak. All regularly grow hea\'ier as the shell 

 grows older and increase by implantation, so that four or five finer 

 striae are embraced by two coarser. The greatest convexity of the 

 pedicle-valve is between one half and two thirds the distance from 

 beak to anterior margin; at this point there is a rather sharp inflection 

 of the shell. 



The striations on the brachial correspond to those of the pedicle- 

 valve, but are not so pronounced. The concavity of this shell follows 

 closely the convexity of the other like two nested cups. 



The cardinal area is narrow, scarcely two millimeters wide at the 

 most. Pedicle-opening very minute, just visible to the eye. 



Three typical specimens measured : — 



Holotype, 



Rafinesquina rugulifera, sp. nov. 



Rafinesquina alternata var. loxorhytis Winchell and Schuchert (not Meek), 

 Geol. Minn., 1893, 3, pt. 1, p. 407, pi. 31, fig. 3.5-37; pi. 32, fig. 59, 60. 



Shell much broader than long, widest at the hinge, which projects 

 into broad "ears" which are demarked by shallow depressions. 

 Pedicle-valve gently and rather evenly convex, highest in front of 



