Jan., 1912.] The Arnheim Formation. 453 



PLATE XXII. 



Fig. 1. Dalmanella jugosa. A, B, pedicel valv'es; C, D, brachial valves. 

 E, F, G, interiors of brachial valves; H, interior of pedicel valve. 

 Arnheim bed, south of Arnheim, Ohio. 



Fig. 2. Heterospongia subramosa-knotti. Lateral view showing osculum 

 surrounded by radiating channels. Arnheim bed, northwest of 

 home of Col. J. B. Wathen, about a mile west of Lebanon, Ky. 



Fig. 3. Platystrophia cypha-conradi. A, pedicel valve; B, C, anterior 

 views. Arnheim bed, half a mile south of Smithville, in Bullitt 

 County, Kentucky. These figures, in the order named, represent 

 other views of the specimens illustrated by figures 14 A, 7 B, and 

 7 A, on Plate IV, in Volume XVI, of the Bulletin, Scientific 

 Laboratories, Denison University, 1910. 



Fig. 4. Platystrophia with outline of PI. clarksvillensis, but the prominent 

 median fold on the brachial valve has the two median plica- 

 tions much more conspicuously elevated than the lateral ones on 

 the fold, as in PI. cypha, to which it is closely related. Arnheim 

 bed, south of Arnheim, Ohio. • 



Fig. 5. Platystrophia cypha. Anterior view of specimen represented by 

 Figure 5, on Plate III, Bulletin, Denison University, 1910. Arn- 

 heim bed, three miles south of Maysville, Kentucky, in deep 

 railroad cut. 



Fig. G. Platystrophia wallowayi. A, brachial valve; B, C, posterior views; 

 D, anterior view; E, lateral view with the beaks directed down- 

 ward. Arnheim bed, on Walloway Creek, two miles south of 

 Rileys, in Marion County, Kentucky. Horizon, 15 feet above the 

 lowest strata containing Leptaena richmondensis. A globose form 

 with rather strong growth striae in the majority of specimens. 



Fig. 7. Leptaena richmondensis-precursor. Brachial valve. Arnheim bed, 

 one mile south of Pisgah, in the southeastern corner of Butler 

 County, Ohio. 



Fig. S. Dinorthis carleyi. A, brachial valve; B, C, pedicel valves; D, 

 interior of pedicel valve. Arnheim bed, Oregonia, Ohio. In 

 Dinorthis retrorsa, of Wales, the median part of the brachial 

 valve is figured as more angular in its elevation, with somewhat 

 flattened lateral slopes. 



Fig. 9. Rhynchotrema dentata-arnheimensis. A, pedicel valve, from 

 Arnheim, Ohio, from same .specimen as Fig. 12, Plate IV, Volume 

 XIV, Bulletin, Denison Univ., 1909. B, lateral view, of specimen 

 from Mount Washington, Bullitt County, Kentucky. Arnheim 

 bed. 



Fig. 10. Strophemona concordensis. A, interior of brachial valve, three 

 miles south of Maysville, Kentucky; B, interior of pedicel valve, 

 more abruptly thickened along the anterior and lateral margin 

 than in the great majority of .specimens. Arnheim, bed, on Eddies 

 Run, in Adams County, one mile east of Clermont County, along 

 the pike from West Union to Decatur, Ohio. 



Fig. 11. Platystrophia ponderosa. Pedicel valve, rather strongly water 

 worn, with holes bored by some other animal. Arnheim bed, 

 south of Arnheim, Ohio. 



