PLATE Vc. 



(Figures 1, '2, H-IS, '25-41, l)v R. I'. Win ri'i i:i.i); 4,."), I'.i, 4-2-17, l)y K. IOmmiins; :>, -20 24, liy.I. C. Mc:Cc)NNki,i..i 



Legend. A- Deltuluim. :i. Anterior adductor suais. 



t. Teeth. a'. Posterior adduetor scars. 



1). Sockets. r. Diductor scars, 



fp. Crural plates. o. Ovarian mai-king-s. 



J. Cardinal process. v. Vascular msirking-s. 



c. Crui'a. 



DALMANELLA, nom. nov. 



I'agu iOi'i. 

 OUTHIS EMACERATA, Hall. 



Fig. 1. The central cardinal portion of the interior of a lu-acliial valve; showing the proce.sses and 



musculai' imprints. X 3. 

 Fig. 2. The exterior of a brachial valve. 



Hudson River group. Cincinnati, Ohio. 

 For further illustration, see Palieontology of Ohio, Volume 1, plate viii. litrs. I, 'J. 



OuTHis Meeki, Miller. 



Fig. 3. The interior of a brachial valve ; showing the cardinal process, crura and muscular scars. The 

 apparent impressions in the umbo-lateral regions are due to abnoi-raal thickening of the test. 

 X 2. 



Hudson River group. Spring Valley, Minnesota. 



Orthis Stonensis, Saffoi'd. 



Fig. 4. Protile of a specimen with valves conjoined. X 2. 



Fig. o. A view of the pedicle-valve of the same specimen ; showing the alternating, fasciculate character 

 of the I'adi.ating striae. X 2. 



Ortiils sub.equata. Coiirail. 



Fig. 6. A view of the brachial valve of the oiigiiial specimen ; .showing the area and foi-amen of the op- 

 posite valve. 

 Figs. 7, 8. Pi-otile and cardinal views of the same. 

 Fig. 9. The articular and muscular area of the In'achial valve. X 3. 

 Figs. 10, 11. Interiors of the pedicle and bi-achial valves. 



Trenton horizon. Mineral Point, Wl^co^isin. 

 For further illustration, see Palieontology of New York. Volume I, plate xxxii, tig. 2. 



Orthis perveta, Conrad. 

 Fig. 12. View fi-om the brachial valve of the original specimen. 

 Figs. 13, 14. Brachial and profile views of a larger individual. 



Trenton horizon. Mineral Point, Wisconsin. 

 For further illustration, .see Palaeontology of New York, Volume I, plate xxxii, tig. 5. 



Orthis elegantula, Dal man. 



Figs. 15, 16. Opposite sides of the same individual ; showing the foi-m of the species as occurring at this 



locality. 

 Fig. 17. The interior of a pedicle-valve, somewhat enlarged. 

 Fig. 18. The interior of a brachial valve ; showing the muscular impressions and articular processes. X 2. 



Niagara group. Waldron, Indiana. 

 Fig. 19. Cardinal view of the centi-al portion of the Ijrachial valve ; showing the composition of the cardi- 

 nal process, the great elevation of the crural plates and crura, and their furrowe<l or crenulated 

 outer walls. X 3. 



Upper Silurian limestone. Island of Qotland. 

 For further illustration, see David.sox, Silurian Brachiopoda, pi. xxvii, figs. 1-9 ; Hall, Twenty- 

 eighth Kept. N. Y. State Mus. Nat. Hist., pi. xxi, figs. 11-17. 



